Apparatus and method for sending and receiving broadcast signals

ABSTRACT

Disclosed herein is a broadcast signal transmitter. A broadcast signal transmitter according to an embodiment of the present invention includes an input formatting module configured to perform baseband formatting and to output the data of at least one Physical Layer Pipe (PLP), a BICM module configured to perform error-correction processing on the PLP data, a framing and interleaving module configured to interleave the PLP data and to generate a signal frame, and a waveform generation module configured to insert a preamble into the signal frame and to generate a broadcast signal by performing OFDM modulation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Provisional Application No.62/111,672 filed on 4 Feb., 2015 in U.S. Provisional Application No.62/184,908 filed on 26 Jun., 2015 in U.S. Provisional Application No.62/183,680 filed on 23 Jun., 2015 in U.S. Provisional Application No.62/135,693 filed on 19 Mar., 2015 in US and Provisional Application No.62/144,897 filed on 8 Apr., 2015 in US. The entire contents of all theseapplications are hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for transmitting broadcastsignals, an apparatus for receiving broadcast signals and methods fortransmitting and receiving broadcast signals.

2. Discussion of the Related Art

As analog broadcast signal transmission comes to an end, varioustechnologies for transmitting/receiving digital broadcast signals arebeing developed. A digital broadcast signal may include a larger amountof video/audio data than an analog broadcast signal and further includevarious types of additional data in addition to the video/audio data.

That is, a digital broadcast system can provide HD (high definition)images, multi-channel audio and various additional services. However,data transmission efficiency for transmission of large amounts of data,robustness of transmission/reception networks and network flexibility inconsideration of mobile reception equipment need to be improved fordigital broadcast.

SUMMARY OF THE INVENTION

A broadcast signal transmitter for processing a broadcast signalincluding signaling information according to an embodiment of thepresent invention includes an input formatting module configured toinput-process input data and to output at least one Physical Layer Pipe(PLP) data by processing the input data, a Bit Interleaved and CodedModulation (BICM) module configured to perform error correctionprocessing on the PLP data, a framing module configured to generate asignal frame including the PLP data, the signal frame including abootstrap, a preamble, and a data part, a pilot insertion moduleconfigured to insert pilots into the signal frame, and an Inverse FastFourier Transform (IFFT) module configured to Orthogonal FrequencyDivision Multiplexing (OFDM)-modulate the signal frame. The bootstrapincludes preamble structure information about the preamble, the preambleincludes at least one preamble symbol, and the at least one preamblesymbol carries L1 signaling data for the signal frame.

In the broadcast signal transmitter according to an embodiment of thepresent invention, the preamble structure information may indicatemodulation/coding mode, a Fast Fourier Transform (FFT) size, a GuardInterval (GI) length, and a pilot pattern of the preamble.

In the broadcast signal transmitter according to an embodiment of thepresent invention, the first preamble symbol of the preamble may includepreamble_symbol_number information indicating the number of preamblesymbols. The preamble_symbol_number information may indicate the numberof additional preamble symbols other than the first preamble symbol.

In the broadcast signal transmitter according to an embodiment of thepresent invention, the first preamble symbol of the preamble may have aminimum number of carriers (NoC). The first preamble symbol may includeNoC-related information indicating the NoC for remaining preamblesymbols other than the first preamble symbol.

In the broadcast signal transmitter according to an embodiment of thepresent invention, the preamble symbol may include preamble pilots. Forthe preamble pilots, the number of symbols Dy forming one pilot sequencein a time direction may be 1, and the separation of pilots Dx in afrequency direction may be indicated by the pilot pattern of thepreamble structure information.

In the broadcast signal transmitter according to an embodiment of thepresent invention, the L1 signaling data may include L1-basic data andL1 detail data. The L1-basic data may include static signalinginformation about the signal frame and define parameters for decodingthe L1 detail data. The L1 detail data may include information fordecoding the data part. The modulation/coding mode may indicatemodulation/coding mode of the L1-basic data.

A method of transmitting a broadcast signal according to an embodimentof the present invention includes input-processing input data andoutputting at least one Physical Layer Pipe (PLP) data by processing theinput data, performing error correction processing on the PLP data,generating a signal frame including the PLP data, the signal frameincluding a bootstrap, a preamble, and a data part, inserting pilotsinto the signal frame, and Orthogonal Frequency Division Multiplexing(OFDM)-modulating the signal frame. The bootstrap includes preamblestructure information about the preamble, the preamble includes at leastone preamble symbol, and the at least one preamble symbol carries L1signaling data for the signal frame.

The present invention can process data according to servicecharacteristics to control QoS (Quality of Services) for each service orservice component, thereby providing various broadcast services.

The present invention can achieve transmission flexibility bytransmitting various broadcast services through the same RF signalbandwidth.

The present invention can improve data transmission efficiency andincrease robustness of transmission/reception of broadcast signals usinga MIMO system.

According to the present invention, it is possible to provide broadcastsignal transmission and reception methods and apparatus capable ofreceiving digital broadcast signals without error even with mobilereception equipment or in an indoor environment.

Further aspects and effects of the present invention will be describedmore detail with embodiments in belows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a structure of an apparatus for transmittingbroadcast signals for future broadcast services according to anembodiment of the present invention.

FIG. 2 illustrates an input formatting block according to one embodimentof the present invention.

FIG. 3 illustrates an input formatting block according to anotherembodiment of the present invention.

FIG. 4 illustrates an input formatting block according to anotherembodiment of the present invention.

FIG. 5 illustrates a BICM block according to an embodiment of thepresent invention.

FIG. 6 illustrates a BICM block according to another embodiment of thepresent invention.

FIG. 7 illustrates a frame building block according to one embodiment ofthe present invention.

FIG. 8 illustrates an OFDM generation block according to an embodimentof the present invention.

FIG. 9 illustrates a structure of an apparatus for receiving broadcastsignals for future broadcast services according to an embodiment of thepresent invention.

FIG. 10 illustrates a frame structure according to an embodiment of thepresent invention.

FIG. 11 illustrates a signaling hierarchy structure of the frameaccording to an embodiment of the present invention.

FIG. 12 illustrates preamble signaling data according to an embodimentof the present invention.

FIG. 13 illustrates PLS1 data according to an embodiment of the presentinvention.

FIG. 14 illustrates PLS2 data according to an embodiment of the presentinvention.

FIG. 15 illustrates PLS2 data according to another embodiment of thepresent invention.

FIG. 16 illustrates a logical structure of a frame according to anembodiment of the present invention.

FIG. 17 illustrates PLS mapping according to an embodiment of thepresent invention.

FIG. 18 illustrates EAC mapping according to an embodiment of thepresent invention.

FIG. 19 illustrates FIC mapping according to an embodiment of thepresent invention.

FIG. 20 illustrates a type of DP according to an embodiment of thepresent invention.

FIG. 21 illustrates DP mapping according to an embodiment of the presentinvention.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention.

FIG. 23 illustrates a bit interleaving according to an embodiment of thepresent invention.

FIG. 24 illustrates a cell-word demultiplexing according to anembodiment of the present invention.

FIG. 25 illustrates a time interleaving according to an embodiment ofthe present invention.

FIG. 26 illustrates a basic operation of a twisted row-column blockinterleaver according to an exemplary embodiment of the presentinvention.

FIG. 27 illustrates an operation of a twisted row-column blockinterleaver according to another exemplary embodiment of the presentinvention.

FIG. 28 illustrates a diagonal reading pattern of the twisted row-columnblock interleaver according to the exemplary embodiment of the presentinvention.

FIG. 29 illustrates XFECBLOCK interleaved from each interleaving arrayaccording to an exemplary embodiment of the present invention.

FIG. 30 shows the configuration of a broadcast signal transmitteraccording to another embodiment of the present invention.

FIG. 31 shows the pilot structure of a signal frame according to anembodiment of the present invention.

FIG. 32 shows the structure of a signal frame according to an embodimentof the present invention.

FIG. 33 shows the structure of a signal frame according to anotherembodiment of the present invention.

FIG. 34 shows the structure of a signal frame according to anotherembodiment of the present invention.

FIG. 35 shows the structure of a signal frame according to anotherembodiment of the present invention.

FIG. 36 shows the structure of a signal frame according to anotherembodiment of the present invention.

FIG. 37 shows the structure of a signal frame according to anotherembodiment of the present invention.

FIG. 38 shows a preamble structure indicator according to an embodimentof the present invention.

FIG. 39 shows a preamble structure indicator according to anotherembodiment of the present invention.

FIG. 40 shows a preamble structure indicator according to anotherembodiment of the present invention.

FIG. 41 shows a preamble structure indicator according to anotherembodiment of the present invention.

FIG. 42 shows a preamble structure indicator according to anotherembodiment of the present invention.

FIG. 43 shows a preamble structure indicator according to anotherembodiment of the present invention.

FIG. 44 shows a preamble structure indicator according to anotherembodiment of the present invention.

FIG. 45 shows an SP-GI combination table of maximum GI utilization modein accordance with an embodiment of the present invention.

FIG. 46 shows an SP-GI combination table of post-GI equalization mode inaccordance with an embodiment of the present invention.

FIG. 47 shows an SP pattern table according to an embodiment of thepresent invention.

FIG. 48 shows a modulation/coding mode table according to an embodimentof the present invention.

FIG. 49 shows a preamble cell mapping method according to an embodimentof the present invention.

FIG. 50 shows a preamble cell mapping method according to anotherembodiment of the present invention.

FIG. 51 shows preamble parameters according to another embodiment of thepresent invention.

FIG. 52 shows the structure of a signal frame according to an embodimentof the present invention.

FIG. 53 shows the structure of a signal frame according to anotherembodiment of the present invention.

FIG. 54 shows the structure of a signal frame according to anotherembodiment of the present invention.

FIG. 55 shows the structure and signaling of a signal frame according toan embodiment of the present invention.

FIG. 56 shows a method of transmitting a broadcast signal according toan embodiment of the present invention.

FIG. 57 shows the synchronization and demodulation module of thebroadcast signal receiver in accordance with an embodiment of thepresent invention.

FIG. 58 shows a method of receiving a broadcast signal according to anembodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The detailed description, which will be given below withreference to the accompanying drawings, is intended to explain exemplaryembodiments of the present invention, rather than to show the onlyembodiments that can be implemented according to the present invention.The following detailed description includes specific details in order toprovide a thorough understanding of the present invention. However, itwill be apparent to those skilled in the art that the present inventionmay be practiced without such specific details.

Although most terms used in the present invention have been selectedfrom general ones widely used in the art, some terms have beenarbitrarily selected by the applicant and their meanings are explainedin detail in the following description as needed. Thus, the presentinvention should be understood based upon the intended meanings of theterms rather than their simple names or meanings. Also, the term blockand module are used similarly to indicate logical/functional unit ofparticular signal/data processing.

The present invention provides apparatuses and methods for transmittingand receiving broadcast signals for future broadcast services. Futurebroadcast services according to an embodiment of the present inventioninclude a terrestrial broadcast service, a mobile broadcast service, aUHDTV service, etc. The present invention may process broadcast signalsfor the future broadcast services through non-MIMO (Multiple InputMultiple Output) or MIMO according to one embodiment. A non-MIMO schemeaccording to an embodiment of the present invention may include a MISO(Multiple Input Single Output) scheme, a SISO (Single Input SingleOutput) scheme, etc.

While MISO or MIMO uses two antennas in the following for convenience ofdescription, the present invention is applicable to systems using two ormore antennas.

The present invention may defines three physical layer (PL)profiles—base, handheld and advanced profiles—each optimized to minimizereceiver complexity while attaining the performance required for aparticular use case. The physical layer (PHY) profiles are subsets ofall configurations that a corresponding receiver should implement.

The three PHY profiles share most of the functional blocks but differslightly in specific blocks and/or parameters. Additional PHY profilescan be defined in the future. For the system evolution, future profilescan also be multiplexed with the existing profiles in a single RFchannel through a future extension frame (FEF). The details of each PHYprofile are described below.

1. Base Profile

The base profile represents a main use case for fixed receiving devicesthat are usually connected to a roof-top antenna. The base profile alsoincludes portable devices that could be transported to a place butbelong to a relatively stationary reception category. Use of the baseprofile could be extended to handheld devices or even vehicular by someimproved implementations, but those use cases are not expected for thebase profile receiver operation.

Target SNR range of reception is from approximately to 20 dB, whichincludes the 15 dB SNR reception capability of the existing broadcastsystem (e.g. ATSC A/53). The receiver complexity and power consumptionis not as critical as in the battery-operated handheld devices, whichwill use the handheld profile. Key system parameters for the baseprofile are listed in below table 1.

TABLE 1 LDPC codeword length 16K, 64K bits Constellation size 4~10 bpcu(bits per channel use) Time de-interleaving memory ≦2¹⁹ data cells sizePilot patterns Pilot pattern for fixed reception FFT size 16K, 32Kpoints

2. Handheld Profile

The handheld profile is designed for use in handheld and vehiculardevices that operate with battery power. The devices can be moving withpedestrian or vehicle speed. The power consumption as well as thereceiver complexity is very important for the implementation of thedevices of the handheld profile. The target SNR range of the handheldprofile is approximately 0 to 10 dB, but can be configured to reachbelow 0 dB when intended for deeper indoor reception.

In addition to low SNR capability, resilience to the Doppler Effectcaused by receiver mobility is the most important performance attributeof the handheld profile. Key system parameters for the handheld profileare listed in the below table 2.

TABLE 2 LDPC codeword length 16 Kbits Constellation size 2~8 bpcu Timede-interleaving memory ≦2¹⁸ data cells size Pilot patterns Pilotpatterns for mobile and indoor reception FFT size 8K, 16K points

3. Advanced Profile

The advanced profile provides highest channel capacity at the cost ofmore implementation complexity. This profile requires using MIMOtransmission and reception, and UHDTV service is a target use case forwhich this profile is specifically designed. The increased capacity canalso be used to allow an increased number of services in a givenbandwidth, e.g., multiple SDTV or HDTV services.

The target SNR range of the advanced profile is approximately 20 to 30dB. MIMO transmission may initially use existing elliptically-polarizedtransmission equipment, with extension to full-power cross-polarizedtransmission in the future. Key system parameters for the advancedprofile are listed in below table 3.

TABLE 3 LDPC codeword length 16K, 64 Kbits Constellation size 8~12 bpcuTime de-interleaving memory ≦2¹⁹ data cells size Pilot patterns Pilotpattern for fixed reception FFT size 16K, 32K points

In this case, the base profile can be used as a profile for both theterrestrial broadcast service and the mobile broadcast service. That is,the base profile can be used to define a concept of a profile whichincludes the mobile profile. Also, the advanced profile can be dividedadvanced profile for a base profile with MIMO and advanced profile for ahandheld profile with MIMO. Moreover, the three profiles can be changedaccording to intention of the designer.

The following terms and definitions may apply to the present invention.The following terms and definitions can be changed according to design.

auxiliary stream: sequence of cells carrying data of as yet undefinedmodulation and coding, which may be used for future extensions or asrequired by broadcasters or network operators

base data pipe: data pipe that carries service signaling data

baseband frame (or BBFRAME): set of Kbch bits which form the input toone FEC encoding process (BCH and LDPC encoding)

cell: modulation value that is carried by one carrier of the OFDMtransmission

coded block: LDPC-encoded block of PLS1 data or one of the LDPC-encodedblocks of PLS2 data

data pipe: logical channel in the physical layer that carries servicedata or related metadata, which may carry one or multiple service(s) orservice component(s).

data pipe unit: a basic unit for allocating data cells to a DP in aframe.

data symbol: OFDM symbol in a frame which is not a preamble symbol (theframe signaling symbol and frame edge symbol is included in the datasymbol)

DP_ID: this 8-bit field identifies uniquely a DP within the systemidentified by the SYSTEM_ID

dummy cell: cell carrying a pseudo-random value used to fill theremaining capacity not used for PLS signaling, DPs or auxiliary streams

emergency alert channel: part of a frame that carries EAS informationdata

frame: physical layer time slot that starts with a preamble and endswith a frame edge symbol

frame repetition unit: a set of frames belonging to same or differentphysical layer profile including a FEF, which is repeated eight times ina super-frame

fast information channel: a logical channel in a frame that carries themapping information between a service and the corresponding base DP

FECBLOCK: set of LDPC-encoded bits of a DP data

FFT size: nominal FFT size used for a particular mode, equal to theactive symbol period Ts expressed in cycles of the elementary period T

frame signaling symbol: OFDM symbol with higher pilot density used atthe start of a frame in certain combinations of FFT size, guard intervaland scattered pilot (sp) pattern, which carries a part of the PLS data

frame edge symbol: OFDM symbol with higher pilot density used at the endof a frame in certain combinations of FFT size, guard interval andscattered pilot pattern

frame-group: the set of all the frames having the same PHY profile typein a super-frame.

future extension frame: physical layer time slot within the super-framethat could be used for future extension, which starts with a preamble

Futurecast UTB system: proposed physical layer broadcasting system, ofwhich the input is one or more MPEG2-TS or IP or general stream(s) andof which the output is an RF signal

input stream: A stream of data for an ensemble of services delivered tothe end users by the system.

normal data symbol: data symbol excluding the frame signaling symbol andthe frame edge symbol

PHY profile: subset of all configurations that a corresponding receivershould implement

PLS: physical layer signaling data consisting of PLS1 and PLS2

PLS1: a first set of PLS data carried in the FSS symbols having a fixedsize, coding and modulation, which carries basic information about thesystem as well as the parameters needed to decode the PLS2

NOTE: PLS1 data remains constant for the duration of a frame-group.

PLS2: a second set of PLS data transmitted in the FSS symbol, whichcarries more detailed PLS data about the system and the DPs

PLS2 dynamic data: PLS2 data that may dynamically change frame-by-frame

PLS2 static data: PLS2 data that remains static for the duration of aframe-group

preamble signaling data: signaling data carried by the preamble symboland used to identify the basic mode of the system

preamble symbol: fixed-length pilot symbol that carries basic PLS dataand is located in the beginning of a frame

NOTE: The preamble symbol is mainly used for fast initial band scan todetect the system signal, its timing, frequency offset, and FFT-size.

reserved for future use: not defined by the present document but may bedefined in future

super-frame: set of eight frame repetition units

time interleaving block (TI block): set of cells within which timeinterleaving is carried out, corresponding to one use of the timeinterleaver memory

TI group: unit over which dynamic capacity allocation for a particularDP is carried out, made up of an integer, dynamically varying number ofXFECBLOCKs

NOTE: The TI group may be mapped directly to one frame or may be mappedto multiple frames. It may contain one or more TI blocks.

Type 1 DP: DP of a frame where all DPs are mapped into the frame in TDMfashion

Type 2 DP: DP of a frame where all DPs are mapped into the frame in FDMfashion

XFECBLOCK: set of Ncells cells carrying all the bits of one LDPCFECBLOCK

FIG. 1 illustrates a structure of an apparatus for transmittingbroadcast signals for future broadcast services according to anembodiment of the present invention.

The apparatus for transmitting broadcast signals for future broadcastservices according to an embodiment of the present invention can includean input formatting block 1000, a BICM (Bit interleaved coding &modulation) block 1010, a frame structure block 1020, an OFDM(Orthogonal Frequency Division Multiplexing) generation block 1030 and asignaling generation block 1040. A description will be given of theoperation of each module of the apparatus for transmitting broadcastsignals.

IP stream/packets and MPEG2-TS are the main input formats, other streamtypes are handled as General Streams. In addition to these data inputs,Management Information is input to control the scheduling and allocationof the corresponding bandwidth for each input stream. One or multiple TSstream(s), IP stream(s) and/or General Stream(s) inputs aresimultaneously allowed.

The input formatting block 1000 can demultiplex each input stream intoone or multiple data pipe(s), to each of which an independent coding andmodulation is applied. The data pipe (DP) is the basic unit forrobustness control, thereby affecting quality-of-service (QoS). One ormultiple service(s) or service component(s) can be carried by a singleDP. Details of operations of the input formatting block 1000 will bedescribed later.

The data pipe is a logical channel in the physical layer that carriesservice data or related metadata, which may carry one or multipleservice(s) or service component(s).

Also, the data pipe unit: a basic unit for allocating data cells to a DPin a frame.

In the BICM block 1010, parity data is added for error correction andthe encoded bit streams are mapped to complex-value constellationsymbols. The symbols are interleaved across a specific interleavingdepth that is used for the corresponding DP. For the advanced profile,MIMO encoding is performed in the BICM block 1010 and the additionaldata path is added at the output for MIMO transmission. Details ofoperations of the BICM block 1010 will be described later.

The Frame Building block 1020 can map the data cells of the input DPsinto the OFDM symbols within a frame. After mapping, the frequencyinterleaving is used for frequency-domain diversity, especially tocombat frequency-selective fading channels. Details of operations of theFrame Building block 1020 will be described later.

After inserting a preamble at the beginning of each frame, the OFDMGeneration block 1030 can apply conventional OFDM modulation having acyclic prefix as guard interval. For antenna space diversity, adistributed MISO scheme is applied across the transmitters. In addition,a Peak-to-Average Power Reduction (PAPR) scheme is performed in the timedomain. For flexible network planning, this proposal provides a set ofvarious FFT sizes, guard interval lengths and corresponding pilotpatterns. Details of operations of the OFDM Generation block 1030 willbe described later.

The Signaling Generation block 1040 can create physical layer signalinginformation used for the operation of each functional block. Thissignaling information is also transmitted so that the services ofinterest are properly recovered at the receiver side. Details ofoperations of the Signaling Generation block 1040 will be describedlater.

FIGS. 2, 3 and 4 illustrate the input formatting block 1000 according toembodiments of the present invention. A description will be given ofeach figure.

FIG. 2 illustrates an input formatting block according to one embodimentof the present invention. FIG. 2 shows an input formatting module whenthe input signal is a single input stream.

The input formatting block illustrated in FIG. 2 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

The input to the physical layer may be composed of one or multiple datastreams. Each data stream is carried by one DP. The mode adaptationmodules slice the incoming data stream into data fields of the basebandframe (BBF). The system supports three types of input data streams:MPEG2-TS, Internet protocol (IP) and Generic stream (GS). MPEG2-TS ischaracterized by fixed length (188 byte) packets with the first bytebeing a sync-byte (0x47). An IP stream is composed of variable length IPdatagram packets, as signaled within IP packet headers. The systemsupports both IPv4 and IPv6 for the IP stream. GS may be composed ofvariable length packets or constant length packets, signaled withinencapsulation packet headers.

(a) shows a mode adaptation block 2000 and a stream adaptation 2010 forsignal DP and (b) shows a PLS generation block 2020 and a PLS scrambler2030 for generating and processing PLS data. A description will be givenof the operation of each block.

The Input Stream Splitter splits the input TS, IP, GS streams intomultiple service or service component (audio, video, etc.) streams. Themode adaptation module 2010 is comprised of a CRC Encoder, BB (baseband)Frame Slicer, and BB Frame Header Insertion block.

The CRC Encoder provides three kinds of CRC encoding for error detectionat the user packet (UP) level, i.e., CRC-8, CRC-16, and CRC-32. Thecomputed CRC bytes are appended after the UP. CRC-8 is used for TSstream and CRC-32 for IP stream. If the GS stream doesn't provide theCRC encoding, the proposed CRC encoding should be applied.

BB Frame Slicer maps the input into an internal logical-bit format. Thefirst received bit is defined to be the MSB. The BB Frame Slicerallocates a number of input bits equal to the available data fieldcapacity. To allocate a number of input bits equal to the BBF payload,the UP packet stream is sliced to fit the data field of BBF.

BB Frame Header Insertion block can insert fixed length BBF header of 2bytes is inserted in front of the BB Frame. The BBF header is composedof STUFFI (1 bit), SYNOD (13 bits), and RFU (2 bits). In addition to thefixed 2-Byte BBF header, BBF can have an extension field (1 or 3 bytes)at the end of the 2-byte BBF header.

The stream adaptation 2010 is comprised of stuffing insertion block andBB scrambler.

The stuffing insertion block can insert stuffing field into a payload ofa BB frame. If the input data to the stream adaptation is sufficient tofill a BB-Frame, STUFFI is set to ‘0’ and the BBF has no stuffing field.Otherwise STUFFI is set to ‘1’ and the stuffing field is insertedimmediately after the BBF header. The stuffing field comprises two bytesof the stuffing field header and a variable size of stuffing data.

The BB scrambler scrambles complete BBF for energy dispersal. Thescrambling sequence is synchronous with the BBF. The scrambling sequenceis generated by the feed-back shift register.

The PLS generation block 2020 can generate physical layer signaling(PLS) data. The PLS provides the receiver with a means to accessphysical layer DPs. The PLS data consists of PLS1 data and PLS2 data.

The PLS1 data is a first set of PLS data carried in the FSS symbols inthe frame having a fixed size, coding and modulation, which carriesbasic information about the system as well as the parameters needed todecode the PLS2 data. The PLS1 data provides basic transmissionparameters including parameters required to enable the reception anddecoding of the PLS2 data. Also, the PLS1 data remains constant for theduration of a frame-group.

The PLS2 data is a second set of PLS data transmitted in the FSS symbol,which carries more detailed PLS data about the system and the DPs. ThePLS2 contains parameters that provide sufficient information for thereceiver to decode the desired DP. The PLS2 signaling further consistsof two types of parameters, PLS2 Static data (PLS2-STAT data) and PLS2dynamic data (PLS2-DYN data). The PLS2 Static data is PLS2 data thatremains static for the duration of a frame-group and the PLS2 dynamicdata is PLS2 data that may dynamically change frame-by-frame.

Details of the PLS data will be described later.

The PLS scrambler 2030 can scramble the generated PLS data for energydispersal.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 3 illustrates an input formatting block according to anotherembodiment of the present invention.

The input formatting block illustrated in FIG. 3 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

FIG. 3 shows a mode adaptation block of the input formatting block whenthe input signal corresponds to multiple input streams.

The mode adaptation block of the input formatting block for processingthe multiple input streams can independently process the multiple inputstreams.

Referring to FIG. 3, the mode adaptation block for respectivelyprocessing the multiple input streams can include an input streamsplitter 3000, an input stream synchronizer 3010, a compensating delayblock 3020, a null packet deletion block 3030, a head compression block3040, a CRC encoder 3050, a BB frame slicer 3060 and a BB headerinsertion block 3070. Description will be given of each block of themode adaptation block.

Operations of the CRC encoder 3050, BB frame slicer 3060 and BB headerinsertion block 3070 correspond to those of the CRC encoder, BB frameslicer and BB header insertion block described with reference to FIG. 2and thus description thereof is omitted.

The input stream splitter 3000 can split the input TS, IP, GS streamsinto multiple service or service component (audio, video, etc.) streams.

The input stream synchronizer 3010 may be referred as ISSY. The ISSY canprovide suitable means to guarantee Constant Bit Rate (CBR) and constantend-to-end transmission delay for any input data format. The ISSY isalways used for the case of multiple DPs carrying TS, and optionallyused for multiple DPs carrying GS streams.

The compensating delay block 3020 can delay the split TS packet streamfollowing the insertion of ISSY information to allow a TS packetrecombining mechanism without requiring additional memory in thereceiver.

The null packet deletion block 3030, is used only for the TS inputstream case. Some TS input streams or split TS streams may have a largenumber of null-packets present in order to accommodate VBR (variablebit-rate) services in a CBR TS stream. In this case, in order to avoidunnecessary transmission overhead, null-packets can be identified andnot transmitted. In the receiver, removed null-packets can bere-inserted in the exact place where they were originally by referenceto a deleted null-packet (DNP) counter that is inserted in thetransmission, thus guaranteeing constant bit-rate and avoiding the needfor time-stamp (PCR) updating.

The head compression block 3040 can provide packet header compression toincrease transmission efficiency for TS or IP input streams. Because thereceiver can have a priori information on certain parts of the header,this known information can be deleted in the transmitter.

For Transport Stream, the receiver has a-priori information about thesync-byte configuration (0x47) and the packet length (188 Byte). If theinput TS stream carries content that has only one PID, i.e., for onlyone service component (video, audio, etc.) or service sub-component (SVCbase layer, SVC enhancement layer, MVC base view or MVC dependentviews), TS packet header compression can be applied (optionally) to theTransport Stream. IP packet header compression is used optionally if theinput steam is an IP stream.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 4 illustrates an input formatting block according to anotherembodiment of the present invention.

The input formatting block illustrated in FIG. 4 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

FIG. 4 illustrates a stream adaptation block of the input formattingmodule when the input signal corresponds to multiple input streams.

Referring to FIG. 4, the mode adaptation block for respectivelyprocessing the multiple input streams can include a scheduler 4000, an1-Frame delay block 4010, a stuffing insertion block 4020, an in-bandsignaling 4030, a BB Frame scrambler 4040, a PLS generation block 4050and a PLS scrambler 4060. Description will be given of each block of thestream adaptation block.

Operations of the stuffing insertion block 4020, the BB Frame scrambler4040, the PLS generation block 4050 and the PLS scrambler 4060correspond to those of the stuffing insertion block, BB scrambler, PLSgeneration block and the PLS scrambler described with reference to FIG.2 and thus description thereof is omitted.

The scheduler 4000 can determine the overall cell allocation across theentire frame from the amount of FECBLOCKs of each DP. Including theallocation for PLS, EAC and FIC, the scheduler generate the values ofPLS2-DYN data, which is transmitted as in-band signaling or PLS cell inFSS of the frame. Details of FECBLOCK, EAC and FIC will be describedlater.

The 1-Frame delay block 4010 can delay the input data by onetransmission frame such that scheduling information about the next framecan be transmitted through the current frame for in-band signalinginformation to be inserted into the DPs.

The in-band signaling 4030 can insert un-delayed part of the PLS2 datainto a DP of a frame.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 5 illustrates a BICM block according to an embodiment of thepresent invention.

The BICM block illustrated in FIG. 5 corresponds to an embodiment of theBICM block 1010 described with reference to FIG. 1.

As described above, the apparatus for transmitting broadcast signals forfuture broadcast services according to an embodiment of the presentinvention can provide a terrestrial broadcast service, mobile broadcastservice, UHDTV service, etc.

Since QoS (quality of service) depends on characteristics of a serviceprovided by the apparatus for transmitting broadcast signals for futurebroadcast services according to an embodiment of the present invention,data corresponding to respective services needs to be processed throughdifferent schemes. Accordingly, the a BICM block according to anembodiment of the present invention can independently process DPs inputthereto by independently applying SISO, MISO and MIMO schemes to thedata pipes respectively corresponding to data paths. Consequently, theapparatus for transmitting broadcast signals for future broadcastservices according to an embodiment of the present invention can controlQoS for each service or service component transmitted through each DP.

(a) shows the BICM block shared by the base profile and the handheldprofile and (b) shows the BICM block of the advanced profile.

The BICM block shared by the base profile and the handheld profile andthe BICM block of the advanced profile can include plural processingblocks for processing each DP.

A description will be given of each processing block of the BICM blockfor the base profile and the handheld profile and the BICM block for theadvanced profile.

A processing block 5000 of the BICM block for the base profile and thehandheld profile can include a Data FEC encoder 5010, a bit interleaver5020, a constellation mapper 5030, an SSD (Signal Space Diversity)encoding block 5040 and a time interleaver 5050.

The Data FEC encoder 5010 can perform the FEC encoding on the input BBFto generate FECBLOCK procedure using outer coding (BCH), and innercoding (LDPC). The outer coding (BCH) is optional coding method. Detailsof operations of the Data FEC encoder 5010 will be described later.

The bit interleaver 5020 can interleave outputs of the Data FEC encoder5010 to achieve optimized performance with combination of the LDPC codesand modulation scheme while providing an efficiently implementablestructure. Details of operations of the bit interleaver 5020 will bedescribed later.

The constellation mapper 5030 can modulate each cell word from the bitinterleaver 5020 in the base and the handheld profiles, or cell wordfrom the Cell-word demultiplexer 5010-1 in the advanced profile usingeither QPSK, QAM-16, non-uniform QAM (NUQ-64, NUQ-256, NUQ-1024) ornon-uniform constellation (NUC-16, NUC-64, NUC-256, NUC-1024) to give apower-normalized constellation point, el. This constellation mapping isapplied only for DPs. Observe that QAM-16 and NUQs are square shaped,while NUCs have arbitrary shape. When each constellation is rotated byany multiple of 90 degrees, the rotated constellation exactly overlapswith its original one. This “rotation-sense” symmetric property makesthe capacities and the average powers of the real and imaginarycomponents equal to each other. Both NUQs and NUCs are definedspecifically for each code rate and the particular one used is signaledby the parameter DP_MOD filed in PLS2 data.

The SSD encoding block 5040 can precode cells in two (2D), three (3D),and four (4D) dimensions to increase the reception robustness underdifficult fading conditions.

The time interleaver 5050 can operates at the DP level. The parametersof time interleaving (TI) may be set differently for each DP. Details ofoperations of the time interleaver 5050 will be described later.

A processing block 5000-1 of the BICM block for the advanced profile caninclude the Data FEC encoder, bit interleaver, constellation mapper, andtime interleaver. However, the processing block 5000-1 is distinguishedfrom the processing block 5000 further includes a cell-worddemultiplexer 5010-1 and a MIMO encoding block 5020-1.

Also, the operations of the Data FEC encoder, bit interleaver,constellation mapper, and time interleaver in the processing block5000-1 correspond to those of the Data FEC encoder 5010, bit interleaver5020, constellation mapper 5030, and time interleaver 5050 described andthus description thereof is omitted.

The cell-word demultiplexer 5010-1 is used for the DP of the advancedprofile to divide the single cell-word stream into dual cell-wordstreams for MIMO processing. Details of operations of the cell-worddemultiplexer 5010-1 will be described later.

The MIMO encoding block 5020-1 can processing the output of thecell-word demultiplexer 5010-1 using MIMO encoding scheme. The MIMOencoding scheme was optimized for broadcasting signal transmission. TheMIMO technology is a promising way to get a capacity increase but itdepends on channel characteristics. Especially for broadcasting, thestrong LOS component of the channel or a difference in the receivedsignal power between two antennas caused by different signal propagationcharacteristics makes it difficult to get capacity gain from MIMO. Theproposed MIMO encoding scheme overcomes this problem using arotation-based pre-coding and phase randomization of one of the MIMOoutput signals.

MIMO encoding is intended for a 2×2 MIMO system requiring at least twoantennas at both the transmitter and the receiver. Two MIMO encodingmodes are defined in this proposal; full-rate spatial multiplexing(FR-SM) and full-rate full-diversity spatial multiplexing (FRFD-SM). TheFR-SM encoding provides capacity increase with relatively smallcomplexity increase at the receiver side while the FRFD-SM encodingprovides capacity increase and additional diversity gain with a greatcomplexity increase at the receiver side. The proposed MIMO encodingscheme has no restriction on the antenna polarity configuration.

MIMO processing is required for the advanced profile frame, which meansall DPs in the advanced profile frame are processed by the MIMO encoder.MIMO processing is applied at DP level. Pairs of the ConstellationMapper outputs NUQ (e1,i and e2,i) are fed to the input of the MIMOEncoder. Paired MIMO Encoder output (g1,i and g2,i) is transmitted bythe same carrier k and OFDM symbol l of their respective TX antennas.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 6 illustrates a BICM block according to another embodiment of thepresent invention.

The BICM block illustrated in FIG. 6 corresponds to an embodiment of theBICM block 1010 described with reference to FIG. 1.

FIG. 6 illustrates a BICM block for protection of physical layersignaling (PLS), emergency alert channel (EAC) and fast informationchannel (FIC). EAC is a part of a frame that carries EAS informationdata and FIC is a logical channel in a frame that carries the mappinginformation between a service and the corresponding base DP. Details ofthe EAC and FIC will be described later.

Referring to FIG. 6, the BICM block for protection of PLS, EAC and FICcan include a PLS FEC encoder 6000, a bit interleaver 6010, aconstellation mapper 6020 and time interleaver 6030.

Also, the PLS FEC encoder 6000 can include a scrambler, BCHencoding/zero insertion block, LDPC encoding block and LDPC paritypunturing block. Description will be given of each block of the BICMblock.

The PLS FEC encoder 6000 can encode the scrambled PLS 1/2 data, EAC andFIC section.

The scrambler can scramble PLS1 data and PLS2 data before BCH encodingand shortened and punctured LDPC encoding.

The BCH encoding/zero insertion block can perform outer encoding on thescrambled PLS 1/2 data using the shortened BCH code for PLS protectionand insert zero bits after the BCH encoding. For PLS1 data only, theoutput bits of the zero insertion may be permutted before LDPC encoding.

The LDPC encoding block can encode the output of the BCH encoding/zeroinsertion block using LDPC code. To generate a complete coded block,Cldpc, parity bits, Pldpc are encoded systematically from eachzero-inserted PLS information block, Ildpc and appended after it.

C _(ldpc) =[I _(ldpc) P _(ldpc) ]=[i ₀ ,i ₁ , . . . ,i _(K) _(ldpc) ₋₁,p ₀ ,p ₁ , . . . ,p _(N) _(ldpc) _(-K) _(ldpc) ₋₁]  [Equation 1]

The LDPC code parameters for PLS1 and PLS2 are as following table 4.

TABLE 4 Signaling Kldpc code Type Ksig Kbch Nbch_parity (=Nbch) NldpcNldpc_parity rate Qldpc PLS1 342 1020 60 1080 4320 3240 1/4  36 PLS2<1021 >1020 2100 2160 7200 5040 3/10 56

The LDPC parity punturing block can perform puncturing on the PLS1 dataand PLS 2 data.

When shortening is applied to the PLS1 data protection, some LDPC paritybits are punctured after LDPC encoding. Also, for the PLS2 dataprotection, the LDPC parity bits of PLS2 are punctured after LDPCencoding. These punctured bits are not transmitted.

The bit interleaver 6010 can interleave the each shortened and puncturedPLS1 data and PLS2 data.

The constellation mapper 6020 can map the bit ineterlaeved PLS1 data andPLS2 data onto constellations.

The time interleaver 6030 can interleave the mapped PLS1 data and PLS2data.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 7 illustrates a frame building block according to one embodiment ofthe present invention.

The frame building block illustrated in FIG. 7 corresponds to anembodiment of the frame building block 1020 described with reference toFIG. 1.

Referring to FIG. 7, the frame building block can include a delaycompensation block 7000, a cell mapper 7010 and a frequency interleaver7020. Description will be given of each block of the frame buildingblock.

The delay compensation block 7000 can adjust the timing between the datapipes and the corresponding PLS data to ensure that they are co-timed atthe transmitter end. The PLS data is delayed by the same amount as datapipes are by addressing the delays of data pipes caused by the InputFormatting block and BICM block. The delay of the BICM block is mainlydue to the time interleaver 5050. In-band signaling data carriesinformation of the next TI group so that they are carried one frameahead of the DPs to be signaled. The Delay Compensating block delaysin-band signaling data accordingly.

The cell mapper 7010 can map PLS, EAC, FIC, DPs, auxiliary streams anddummy cells into the active carriers of the OFDM symbols in the frame.The basic function of the cell mapper 7010 is to map data cells producedby the TIs for each of the DPs, PLS cells, and EAC/FIC cells, if any,into arrays of active OFDM cells corresponding to each of the OFDMsymbols within a frame. Service signaling data (such as PSI (programspecific information)/SI) can be separately gathered and sent by a datapipe. The Cell Mapper operates according to the dynamic informationproduced by the scheduler and the configuration of the frame structure.Details of the frame will be described later.

The frequency interleaver 7020 can randomly interleave data cellsreceived from the cell mapper 7010 to provide frequency diversity. Also,the frequency interleaver 7020 can operate on very OFDM symbol paircomprised of two sequential OFDM symbols using a differentinterleaving-seed order to get maximum interleaving gain in a singleframe. Details of operations of the frequency interleaver 7020 will bedescribed later.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 8 illustrates an OFMD generation block according to an embodimentof the present invention.

The OFMD generation block illustrated in FIG. 8 corresponds to anembodiment of the OFMD generation block 1030 described with reference toFIG. 1.

The OFDM generation block modulates the OFDM carriers by the cellsproduced by the Frame Building block, inserts the pilots, and producesthe time domain signal for transmission. Also, this block subsequentlyinserts guard intervals, and applies PAPR (Peak-to-Average Power Radio)reduction processing to produce the final RF signal.

Referring to FIG. 8, the frame building block can include a pilot andreserved tone insertion block 8000, a 2D-eSFN encoding block 8010, anIFFT (Inverse Fast Fourier Transform) block 8020, a PAPR reduction block8030, a guard interval insertion block 8040, a preamble insertion block8050, other system insertion block 8060 and a DAC block 8070.Description will be given of each block of the frame building block.

The pilot and reserved tone insertion block 8000 can insert pilots andthe reserved tone.

Various cells within the OFDM symbol are modulated with referenceinformation, known as pilots, which have transmitted values known apriori in the receiver. The information of pilot cells is made up ofscattered pilots (SP), continual pilots (CP), edge pilots (EP), FSS(frame signaling symbol) pilots and FES (frame edge symbol) pilots. Eachpilot is transmitted at a particular boosted power level according topilot type and pilot pattern. The value of the pilot information isderived from a reference sequence, which is a series of values, one foreach transmitted carrier on any given symbol. The pilots can be used forframe synchronization, frequency synchronization, time synchronization,channel estimation, and transmission mode identification, and also canbe used to follow the phase noise.

Reference information, taken from the reference sequence, is transmittedin scattered pilot cells in every symbol except the preamble, FSS andFES of the frame. Continual pilots are inserted in every symbol of theframe. The number and location of continual pilots depends on both theFFT size and the scattered pilot pattern. The edge carriers are edgepilots in every symbol except for the preamble symbol. They are insertedin order to allow frequency interpolation up to the edge of thespectrum. FSS pilots are inserted in FSS(s) and FES pilots are insertedin FES. They are inserted in order to allow time interpolation up to theedge of the frame.

The system according to an embodiment of the present invention supportsthe SFN network, where distributed MISO scheme is optionally used tosupport very robust transmission mode. The 2D-eSFN is a distributed MISOscheme that uses multiple TX antennas, each of which is located in thedifferent transmitter site in the SFN network. The 2D-eSFN encodingblock 8010 can process a 2D-eSFN processing to distorts the phase of thesignals transmitted from multiple transmitters, in order to create bothtime and frequency diversity in the SFN configuration. Hence, bursterrors due to low flat fading or deep-fading for a long time can bemitigated.

The IFFT block 8020 can modulate the output from the 2D-eSFN encodingblock 8010 using OFDM modulation scheme. Any cell in the data symbolswhich has not been designated as a pilot (or as a reserved tone) carriesone of the data cells from the frequency interleaver. The cells aremapped to OFDM carriers.

The PAPR reduction block 8030 can perform a PAPR reduction on inputsignal using various PAPR reduction algorithm in the time domain.

The guard interval insertion block 8040 can insert guard intervals andthe preamble insertion block 8050 can insert preamble in front of thesignal. Details of a structure of the preamble will be described later.The other system insertion block 8060 can multiplex signals of aplurality of broadcast transmission/reception systems in the time domainsuch that data of two or more different broadcast transmission/receptionsystems providing broadcast services can be simultaneously transmittedin the same RF signal bandwidth. In this case, the two or more differentbroadcast transmission/reception systems refer to systems providingdifferent broadcast services. The different broadcast services may referto a terrestrial broadcast service, mobile broadcast service, etc. Datarelated to respective broadcast services can be transmitted throughdifferent frames.

The DAC block 8070 can convert an input digital signal into an analogsignal and output the analog signal. The signal output from the DACblock 7800 can be transmitted through multiple output antennas accordingto the physical layer profiles. A Tx antenna according to an embodimentof the present invention can have vertical or horizontal polarity.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to design.

FIG. 9 illustrates a structure of an apparatus for receiving broadcastsignals for future broadcast services according to an embodiment of thepresent invention.

The apparatus for receiving broadcast signals for future broadcastservices according to an embodiment of the present invention cancorrespond to the apparatus for transmitting broadcast signals forfuture broadcast services, described with reference to FIG. 1.

The apparatus for receiving broadcast signals for future broadcastservices according to an embodiment of the present invention can includea synchronization & demodulation module 9000, a frame parsing module9010, a demapping & decoding module 9020, an output processor 9030 and asignaling decoding module 9040. A description will be given of operationof each module of the apparatus for receiving broadcast signals.

The synchronization & demodulation module 9000 can receive input signalsthrough m Rx antennas, perform signal detection and synchronization withrespect to a system corresponding to the apparatus for receivingbroadcast signals and carry out demodulation corresponding to a reverseprocedure of the procedure performed by the apparatus for transmittingbroadcast signals.

The frame parsing module 9010 can parse input signal frames and extractdata through which a service selected by a user is transmitted. If theapparatus for transmitting broadcast signals performs interleaving, theframe parsing module 9010 can carry out deinterleaving corresponding toa reverse procedure of interleaving. In this case, the positions of asignal and data that need to be extracted can be obtained by decodingdata output from the signaling decoding module 9400 to restorescheduling information generated by the apparatus for transmittingbroadcast signals.

The demapping & decoding module 9020 can convert the input signals intobit domain data and then deinterleave the same as necessary. Thedemapping & decoding module 9200 can perform demapping for mappingapplied for transmission efficiency and correct an error generated on atransmission channel through decoding. In this case, the demapping &decoding module 9020 can obtain transmission parameters necessary fordemapping and decoding by decoding the data output from the signalingdecoding module 9040.

The output processor 9030 can perform reverse procedures of variouscompression/signal processing procedures which are applied by theapparatus for transmitting broadcast signals to improve transmissionefficiency. In this case, the output processor 9030 can acquirenecessary control information from data output from the signalingdecoding module 9040. The output of the output processor 9030corresponds to a signal input to the apparatus for transmittingbroadcast signals and may be MPEG-TSs, IP streams (v4 or v6) and genericstreams.

The signaling decoding module 9040 can obtain PLS information from thesignal demodulated by the synchronization & demodulation module 9000. Asdescribed above, the frame parsing module 9010, demapping & decodingmodule 9020 and output processor 9030 can execute functions thereofusing the data output from the signaling decoding module 9040.

FIG. 10 illustrates a frame structure according to an embodiment of thepresent invention.

FIG. 10 shows an example configuration of the frame types and FRUs in asuper-frame. (a) shows a super frame according to an embodiment of thepresent invention, (b) shows FRU (Frame Repetition Unit) according to anembodiment of the present invention, (c) shows frames of variable PHYprofiles in the FRU and (d) shows a structure of a frame.

A super-frame may be composed of eight FRUs. The FRU is a basicmultiplexing unit for TDM of the frames, and is repeated eight times ina super-frame.

Each frame in the FRU belongs to one of the PHY profiles, (base,handheld, advanced) or FEF. The maximum allowed number of the frames inthe FRU is four and a given PHY profile can appear any number of timesfrom zero times to four times in the FRU (e.g., base, base, handheld,advanced). PHY profile definitions can be extended using reserved valuesof the PHY_PROFILE in the preamble, if required.

The FEF part is inserted at the end of the FRU, if included. When theFEF is included in the FRU, the minimum number of FEFs is 8 in asuper-frame. It is not recommended that FEF parts be adjacent to eachother.

One frame is further divided into a number of OFDM symbols and apreamble. As shown in (d), the frame comprises a preamble, one or moreframe signaling symbols (FSS), normal data symbols and a frame edgesymbol (FES).

The preamble is a special symbol that enables fast Futurecast UTB systemsignal detection and provides a set of basic transmission parameters forefficient transmission and reception of the signal. The detaileddescription of the preamble will be will be described later.

The main purpose of the FSS(s) is to carry the PLS data. For fastsynchronization and channel estimation, and hence fast decoding of PLSdata, the FSS has more dense pilot pattern than the normal data symbol.The FES has exactly the same pilots as the FSS, which enablesfrequency-only interpolation within the FES and temporal interpolation,without extrapolation, for symbols immediately preceding the FES.

FIG. 11 illustrates a signaling hierarchy structure of the frameaccording to an embodiment of the present invention.

FIG. 11 illustrates the signaling hierarchy structure, which is splitinto three main parts: the preamble signaling data 11000, the PLS1 data11010 and the PLS2 data 11020. The purpose of the preamble, which iscarried by the preamble symbol in every frame, is to indicate thetransmission type and basic transmission parameters of that frame. ThePLS1 enables the receiver to access and decode the PLS2 data, whichcontains the parameters to access the DP of interest. The PLS2 iscarried in every frame and split into two main parts: PLS2-STAT data andPLS2-DYN data. The static and dynamic portion of PLS2 data is followedby padding, if necessary.

FIG. 12 illustrates preamble signaling data according to an embodimentof the present invention.

Preamble signaling data carries 21 bits of information that are neededto enable the receiver to access PLS data and trace DPs within the framestructure. Details of the preamble signaling data are as follows:

PHY_PROFILE: This 3-bit field indicates the PHY profile type of thecurrent frame. The mapping of different PHY profile types is given inbelow table 5.

TABLE 5 Value PHY profile 000 Base profile 001 Handheld profile 010Advanced profiled 011~110 Reserved 111 FEF

FFT_SIZE: This 2 bit field indicates the FFT size of the current framewithin a frame-group, as described in below table 6.

TABLE 6 Value FFT size 00  8K FFT 01 16K FFT 10 32K FFT 11 Reserved

GI_FRACTION: This 3 bit field indicates the guard interval fractionvalue in the current super-frame, as described in below table 7.

TABLE 7 Value GI_FRACTION 000 ⅕ 001 1/10 010 1/20 011 1/40 100 1/80 1011/160 110~111 Reserved

EAC_FLAG: This 1 bit field indicates whether the EAC is provided in thecurrent frame. If this field is set to ‘1’, emergency alert service(EAS) is provided in the current frame. If this field set to ‘0’, EAS isnot carried in the current frame. This field can be switched dynamicallywithin a super-frame.

PILOT_MODE: This 1-bit field indicates whether the pilot mode is mobilemode or fixed mode for the current frame in the current frame-group. Ifthis field is set to ‘0’, mobile pilot mode is used. If the field is setto ‘1’, the fixed pilot mode is used.

PAPR_FLAG: This 1-bit field indicates whether PAPR reduction is used forthe current frame in the current frame-group. If this field is set tovalue ‘1’, tone reservation is used for PAPR reduction. If this field isset to ‘0’, PAPR reduction is not used.

FRU_CONFIGURE: This 3-bit field indicates the PHY profile typeconfigurations of the frame repetition units (FRU) that are present inthe current super-frame. All profile types conveyed in the currentsuper-frame are identified in this field in all preambles in the currentsuper-frame. The 3-bit field has a different definition for eachprofile, as show in below table 8.

TABLE 8 Current Current Current Current PHY_PROFILE = PHY_PROFILE =PHY_PROFILE = PHY_PROFILE = ‘000’ ‘001’ ‘010’ ‘111’ (base) (handheld)(advanced) (FEF) FRU_CONFIGURE = Only base Only Only Only FEF 000profile handheld advanced present present profile profile presentpresent FRU_CONFIGURE = Handheld Base Base Base 1XX profile profileprofile profile present present present present FRU_CONFIGURE = AdvancedAdvanced Handheld Handheld X1X profile profile profile profile presentpresent present present FRU_CONFIGURE = FEF FEF FEF Advanced XX1 presentpresent present profile present

RESERVED: This 7-bit field is reserved for future use.

FIG. 13 illustrates PLS1 data according to an embodiment of the presentinvention.

PLS1 data provides basic transmission parameters including parametersrequired to enable the reception and decoding of the PLS2. As abovementioned, the PLS1 data remain unchanged for the entire duration of oneframe-group. The detailed definition of the signaling fields of the PLS1data are as follows:

PREAMBLE_DATA: This 20-bit field is a copy of the preamble signalingdata excluding the EAC_FLAG.

NUM_FRAME_FRU: This 2-bit field indicates the number of the frames perFRU.

PAYLOAD_TYPE: This 3-bit field indicates the format of the payload datacarried in the frame-group. PAYLOAD_TYPE is signaled as shown in table9.

TABLE 9 Value Payload type 1XX TS stream is transmitted X1X IP stream istransmitted XX1 GS stream is transmitted

NUM_FSS: This 2-bit field indicates the number of FSS symbols in thecurrent frame.

SYSTEM_VERSION: This 8-bit field indicates the version of thetransmitted signal format. The SYSTEM_VERSION is divided into two 4-bitfields, which are a major version and a minor version.

Major version: The MSB four bits of SYSTEM_VERSION field indicate majorversion information. A change in the major version field indicates anon-backward-compatible change. The default value is ‘0000’. For theversion described in this standard, the value is set to ‘0000’.

Minor version: The LSB four bits of SYSTEM_VERSION field indicate minorversion information. A change in the minor version field isbackward-compatible.

CELL_ID: This is a 16-bit field which uniquely identifies a geographiccell in an ATSC network. An ATSC cell coverage area may consist of oneor more frequencies, depending on the number of frequencies used perFuturecast UTB system. If the value of the CELL_ID is not known orunspecified, this field is set to ‘0’.

NETWORK_ID: This is a 16-bit field which uniquely identifies the currentATSC network.

SYSTEM_ID: This 16-bit field uniquely identifies the Futurecast UTBsystem within the ATSC network. The Futurecast UTB system is theterrestrial broadcast system whose input is one or more input streams(TS, IP, GS) and whose output is an RF signal. The Futurecast UTB systemcarries one or more PHY profiles and FEF, if any. The same FuturecastUTB system may carry different input streams and use different RFfrequencies in different geographical areas, allowing local serviceinsertion. The frame structure and scheduling is controlled in one placeand is identical for all transmissions within a Futurecast UTB system.One or more Futurecast UTB systems may have the same SYSTEM_ID meaningthat they all have the same physical layer structure and configuration.

The following loop consists of FRU_ PHY_ PROFILE, FRU_FRAME_LENGTH,FRU_GI_FRACTION, and RESERVED which are used to indicate the FRUconfiguration and the length of each frame type. The loop size is fixedso that four PHY profiles (including a FEF) are signaled within the FRU.If NUM_FRAME_FRU is less than 4, the unused fields are filled withzeros.

FRU_PHY_PROFILE: This 3-bit field indicates the PHY profile type of the(i+1)th (i is the loop index) frame of the associated FRU. This fielduses the same signaling format as shown in the table 8.

FRU_FRAME_LENGTH: This 2-bit field indicates the length of the (i+1)thframe of the associated FRU. Using FRU_FRAME_LENGTH together with FRU_GI_ FRACTION, the exact value of the frame duration can be obtained.

FRU_GI_FRACTION: This 3-bit field indicates the guard interval fractionvalue of the (i+1)th frame of the associated FRU. FRU_GI_FRACTION issignaled according to the table 7.

RESERVED: This 4-bit field is reserved for future use.

The following fields provide parameters for decoding the PLS2 data.

PLS2_FEC_TYPE: This 2-bit field indicates the FEC type used by the PLS2protection. The FEC type is signaled according to table 10. The detailsof the LDPC codes will be described later.

TABLE 10 Contents PLS2 FEC type 00 4K-1/4 and 7K-3/10 LDPC codes 01~11Reserved

PLS2_MOD: This 3-bit field indicates the modulation type used by thePLS2. The modulation type is signaled according to table 11.

TABLE 11 Value PLS2_MODE 000 BPSK 001 QPSK 010 QAM-16 011 NUQ-64 100~111Reserved

PLS2_SIZE_CELL: This 15-bit field indicates Ctotal_partial_block, thesize (specified as the number of QAM cells) of the collection of fullcoded blocks for PLS2 that is carried in the current frame-group. Thisvalue is constant during the entire duration of the current frame-group.

PLS2_STAT_SIZE_BIT: This 14-bit field indicates the size, in bits, ofthe PLS2-STAT for the current frame-group. This value is constant duringthe entire duration of the current frame-group.

PLS2_DYN_SIZE_BIT: This 14-bit field indicates the size, in bits, of thePLS2-DYN for the current frame-group. This value is constant during theentire duration of the current frame-group.

PLS2_REP_FLAG: This 1-bit flag indicates whether the PLS2 repetitionmode is used in the current frame-group. When this field is set to value‘1’, the PLS2 repetition mode is activated. When this field is set tovalue ‘0’, the PLS2 repetition mode is deactivated.

PLS2_REP_SIZE_CELL: This 15-bit field indicates Ctotal_partial_block,the size (specified as the number of QAM cells) of the collection ofpartial coded blocks for PLS2 carried in every frame of the currentframe-group, when PLS2 repetition is used. If repetition is not used,the value of this field is equal to 0. This value is constant during theentire duration of the current frame-group.

PLS2_NEXT_FEC_TYPE: This 2-bit field indicates the FEC type used forPLS2 that is carried in every frame of the next frame-group. The FECtype is signaled according to the table 10.

PLS2_NEXT_MOD: This 3-bit field indicates the modulation type used forPLS2 that is carried in every frame of the next frame-group. Themodulation type is signaled according to the table 11.

PLS2_NEXT_REP_FLAG: This 1-bit flag indicates whether the PLS2repetition mode is used in the next frame-group. When this field is setto value ‘1’, the PLS2 repetition mode is activated. When this field isset to value ‘0’, the PLS2 repetition mode is deactivated.

PLS2_NEXT_REP_SIZE_CELL: This 15-bit field indicates Ctotal_full_block,The size (specified as the number of QAM cells) of the collection offull coded blocks for PLS2 that is carried in every frame of the nextframe-group, when PLS2 repetition is used. If repetition is not used inthe next frame-group, the value of this field is equal to 0. This valueis constant during the entire duration of the current frame-group.

PLS2_NEXT_REP_STAT_SIZE_BIT: This 14-bit field indicates the size, inbits, of the PLS2-STAT for the next frame-group. This value is constantin the current frame-group.

PLS2_NEXT_REP_DYN_SIZE_BIT: This 14-bit field indicates the size, inbits, of the PLS2-DYN for the next frame-group. This value is constantin the current frame-group.

PLS2_AP_MODE: This 2-bit field indicates whether additional parity isprovided for PLS2 in the current frame-group. This value is constantduring the entire duration of the current frame-group. The below table12 gives the values of this field. When this field is set to ‘00’,additional parity is not used for the PLS2 in the current frame-group.

TABLE 12 Value PLS2-AP mode 00 AP is not provided 01 AP1 mode 10~11Reserved

PLS2_AP_SIZE_CELL: This 15-bit field indicates the size (specified asthe number of QAM cells) of the additional parity bits of the PLS2. Thisvalue is constant during the entire duration of the current frame-group.

PLS2_NEXT_AP_MODE: This 2-bit field indicates whether additional parityis provided for PLS2 signaling in every frame of next frame-group. Thisvalue is constant during the entire duration of the current frame-group.The table 12 defines the values of this field

PLS2_NEXT_AP_SIZE_CELL: This 15-bit field indicates the size (specifiedas the number of QAM cells) of the additional parity bits of the PLS2 inevery frame of the next frame-group. This value is constant during theentire duration of the current frame-group.

RESERVED: This 32-bit field is reserved for future use.

CRC_32: A 32-bit error detection code, which is applied to the entirePLS1 signaling.

FIG. 14 illustrates PLS2 data according to an embodiment of the presentinvention.

FIG. 14 illustrates PLS2-STAT data of the PLS2 data. The PLS2-STAT dataare the same within a frame-group, while the PLS2-DYN data provideinformation that is specific for the current frame.

The details of fields of the PLS2-STAT data are as follows:

FIC_FLAG: This 1-bit field indicates whether the FIC is used in thecurrent frame-group. If this field is set to ‘1’, the FIC is provided inthe current frame. If this field set to ‘0’, the FIC is not carried inthe current frame. This value is constant during the entire duration ofthe current frame-group.

AUX_FLAG: This 1-bit field indicates whether the auxiliary stream(s) isused in the current frame-group. If this field is set to ‘1’, theauxiliary stream is provided in the current frame. If this field set to‘0’, the auxiliary stream is not carried in the current frame. Thisvalue is constant during the entire duration of current frame-group.

NUM_DP: This 6-bit field indicates the number of DPs carried within thecurrent frame. The value of this field ranges from 1 to 64, and thenumber of DPs is NUM_DP+1.

DP_ID: This 6-bit field identifies uniquely a DP within a PHY profile.

DP_TYPE: This 3-bit field indicates the type of the DP. This is signaledaccording to the below table 13.

TABLE 13 Value DP Type 000 DP Type 1 001 DP Type 2 010~111 reserved

DP_GROUP_ID: This 8-bit field identifies the DP group with which thecurrent DP is associated. This can be used by a receiver to access theDPs of the service components associated with a particular service,which will have the same DP_GROUP_ID.

BASE_DP_ID: This 6-bit field indicates the DP carrying service signalingdata (such as PSI/SI) used in the Management layer. The DP indicated byBASE_DP_ID may be either a normal DP carrying the service signaling dataalong with the service data or a dedicated DP carrying only the servicesignaling data

DP_FEC_TYPE: This 2-bit field indicates the FEC type used by theassociated DP. The FEC type is signaled according to the below table 14.

TABLE 14 Value FEC_TYPE 00 16K LDPC 01 64K LDPC 10~11 Reserved

DP_COD: This 4-bit field indicates the code rate used by the associatedDP. The code rate is signaled according to the below table 15.

TABLE 15 Value Code rate 0000 5/15 0001 6/15 0010 7/15 0011 8/15 01009/15 0101 10/15  0110 11/15  0111 12/15  1000 13/15  1001~1111 Reserved

DP_MOD: This 4-bit field indicates the modulation used by the associatedDP. The modulation is signaled according to the below table 16.

TABLE 16 Value Modulation 0000 QPSK 0001 QAM-16 0010 NUQ-64 0011 NUQ-2560100 NUQ-1024 0101 NUC-16 0110 NUC-64 0111 NUC-256 1000 NUC-10241001~1111 reserved

DP_SSD_FLAG: This 1-bit field indicates whether the SSD mode is used inthe associated DP. If this field is set to value ‘1’, SSD is used. Ifthis field is set to value ‘0’, SSD is not used.

The following field appears only if PHY_PROFILE is equal to ‘010’, whichindicates the advanced profile:

DP_MIMO: This 3-bit field indicates which type of MIMO encoding processis applied to the associated DP. The type of MIMO encoding process issignaled according to the table 17.

TABLE 17 Value MIMO encoding 000 FR-SM 001 FRFD-SM 010~111 reserved

DP_TI_TYPE: This 1-bit field indicates the type of time-interleaving. Avalue of ‘0’ indicates that one TI group corresponds to one frame andcontains one or more TI-blocks. A value of ‘1’ indicates that one TIgroup is carried in more than one frame and contains only one TI-block.

DP_TI_LENGTH: The use of this 2-bit field (the allowed values are only1, 2, 4, 8) is determined by the values set within the DP_TI_TYPE fieldas follows:

If the DP_TI_TYPE is set to the value ‘1’, this field indicates PI, thenumber of the frames to which each TI group is mapped, and there is oneTI-block per TI group (NTI=1). The allowed PI values with 2-bit fieldare defined in the below table 18.

If the DP_TI_TYPE is set to the value ‘0’, this field indicates thenumber of TI-blocks NTI per TI group, and there is one TI group perframe (Pi=1). The allowed PI values with 2-bit field are defined in thebelow table 18.

TABLE 18 2-bit field PI NTI 00 1 1 01 2 2 10 4 3 11 8 4

DP_FRAME_INTERVAL: This 2-bit field indicates the frame interval (IJUMP)within the frame-group for the associated DP and the allowed values are1, 2, 4, 8 (the corresponding 2-bit field is ‘00’, ‘01’, ‘10’, or ‘11’,respectively). For DPs that do not appear every frame of theframe-group, the value of this field is equal to the interval betweensuccessive frames. For example, if a DP appears on the frames 1, 5, 9,13, etc., this field is set to ‘4’. For DPs that appear in every frame,this field is set to ‘1’.

DP_TI_BYPASS: This 1-bit field determines the availability of timeinterleaver 5050. If time interleaving is not used for a DP, it is setto ‘1’. Whereas if time interleaving is used it is set to ‘0’.

DP_FIRST_FRAME_IDX: This 5-bit field indicates the index of the firstframe of the super-frame in which the current DP occurs. The value ofDP_FIRST_FRAME_IDX ranges from 0 to 31

DP_NUM_BLOCK_MAX: This 10-bit field indicates the maximum value ofDP_NUM_BLOCKS for this DP. The value of this field has the same range asDP_NUM_BLOCKS.

DP_PAYLOAD_TYPE: This 2-bit field indicates the type of the payload datacarried by the given DP. DP_PAYLOAD_TYPE is signaled according to thebelow table 19.

TABLE 19 Value Payload Type 00 TS. 01 IP 10 GS 11 reserved

DP_INBAND_MODE: This 2-bit field indicates whether the current DPcarries in-band signaling information. The in-band signaling type issignaled according to the below table 20.

TABLE 20 Value In-band mode 00 In-band signaling is not carried. 01INBAND-PLS is carried only 10 INBAND-ISSY is carried only 11 INBAND-PLSand INBAND-ISSY are carried

DP_PROTOCOL_TYPE: This 2-bit field indicates the protocol type of thepayload carried by the given DP. It is signaled according to the belowtable 21 when input payload types are selected.

TABLE 21 If If If DP_PAYLOAD_TYPE DP_PAYLOAD_TYPE DP_PAYLOAD_TYPE ValueIs TS Is IP Is GS 00 MPEG2-TS IPv4 (Note) 01 Reserved IPv6 Reserved 10Reserved Reserved Reserved 11 Reserved Reserved Reserved

DP_CRC_MODE: This 2-bit field indicates whether CRC encoding is used inthe Input Formatting block. The CRC mode is signaled according to thebelow table 22.

TABLE 22 Value CRC mode 00 Not used 01 CRC-8 10 CRC-16 11 CRC-32

DNP_MODE: This 2-bit field indicates the null-packet deletion mode usedby the associated DP when DP_PAYLOAD_TYPE is set to TS)(° 00°. DNP_MODEis signaled according to the below table 23. If DP_PAYLOAD_TYPE is notTS (‘00’), DNP_MODE is set to the value ‘00’.

TABLE 23 Value Null-packet deletion mode 00 Not used 01 DNP-NORMAL 10DNP-OFFSET 11 reserved

ISSY_MODE: This 2-bit field indicates the ISSY mode used by theassociated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). The ISSY_MODE issignaled according to the below table 24 If DP_PAYLOAD_TYPE is not TS‘00’), ISSY_MODE is (set to the value ‘00’.

TABLE 24 Value ISSY mode 00 Not used 01 ISSY-UP 10 ISSY-BBF 11 reserved

HC_MODE_TS: This 2-bit field indicates the TS header compression modeused by the associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). TheHC_MODE_TS is signaled according to the below table 25.

TABLE 25 Value Header compression mode 00 HC_MODE_TS 1 01 HC_MODE_TS 210 HC_MODE_TS 3 11 HC_MODE_TS 4

HC_MODE_IP: This 2-bit field indicates the IP header compression modewhen DP_PAYLOAD_TYPE is set to IP (‘01’). The HC_ MODE_ IP is signaledaccording to the below table 26.

TABLE 26 Value Header compression mode 00 No compression 01 HC_MODE_IP 110~11 reserved

PID: This 13-bit field indicates the PID number for TS headercompression when DP_PAYLOAD_TYPE is set to TS (‘00’) and HC_MODE_TS isset to ‘01’ or ‘10’.

RESERVED: This 8-bit field is reserved for future use.

The following field appears only if FIC_FLAG is equal to ‘1’:

FIC_VERSION: This 8-bit field indicates the version number of the FIC.

FIC_LENGTH_BYTE: This 13-bit field indicates the length, in bytes, ofthe FIC.

RESERVED: This 8-bit field is reserved for future use.

The following field appears only if AUX_FLAG is equal to ‘1’:

NUM_AUX: This 4-bit field indicates the number of auxiliary streams.Zero means no auxiliary streams are used.

AUX_CONFIG_RFU: This 8-bit field is reserved for future use.

AUX_STREAM_TYPE: This 4-bit is reserved for future use for indicatingthe type of the current auxiliary stream.

AUX_PRIVATE_CONFIG: This 28-bit field is reserved for future use forsignaling auxiliary streams.

FIG. 15 illustrates PLS2 data according to another embodiment of thepresent invention.

FIG. 15 illustrates PLS2-DYN data of the PLS2 data. The values of thePLS2-DYN data may change during the duration of one frame-group, whilethe size of fields remains constant.

The details of fields of the PLS2-DYN data are as follows:

FRAME_INDEX: This 5-bit field indicates the frame index of the currentframe within the super-frame. The index of the first frame of thesuper-frame is set to ‘0’.

PLS_CHANGE_COUNTER: This 4-bit field indicates the number ofsuper-frames ahead where the configuration will change. The nextsuper-frame with changes in the configuration is indicated by the valuesignaled within this field. If this field is set to the value ‘0000’, itmeans that no scheduled change is foreseen: e.g., value ‘1’ indicatesthat there is a change in the next super-frame.

FIC_CHANGE_COUNTER: This 4-bit field indicates the number ofsuper-frames ahead where the configuration (i.e., the contents of theFIC) will change. The next super-frame with changes in the configurationis indicated by the value signaled within this field. If this field isset to the value ‘0000’, it means that no scheduled change is foreseen:e.g. value ‘0001’ indicates that there is a change in the nextsuper-frame.

RESERVED: This 16-bit field is reserved for future use.

The following fields appear in the loop over NUM_DP, which describe theparameters associated with the DP carried in the current frame.

DP_ID: This 6-bit field indicates uniquely the DP within a PHY profile.

DP_START: This 15-bit (or 13-bit) field indicates the start position ofthe first of the DPs using the DPU addressing scheme. The DP_START fieldhas differing length according to the PHY profile and FFT size as shownin the below table 27.

TABLE 27 DP_START field size PHY profile 64K 16K Base 13 bits 15 bitsHandheld — 13 bits Advanced 13 bits 15 bits

DP_NUM_BLOCK: This 10-bit field indicates the number of FEC blocks inthe current TI group for the current DP. The value of DP_NUM_BLOCKranges from 0 to 1023

RESERVED: This 8-bit field is reserved for future use.

The following fields indicate the FIC parameters associated with theEAC.

EAC_FLAG: This 1-bit field indicates the existence of the EAC in thecurrent frame. This bit is the same value as the EAC_FLAG in thepreamble.

EAS_WAKE_UP_VERSION_NUM: This 8-bit field indicates the version numberof a wake-up indication.

If the EAC_FLAG field is equal to ‘1’, the following 12 bits areallocated for EAC_LENGTH_BYTE field. If the EAC_FLAG field is equal to‘0’, the following 12 bits are allocated for EAC_COUNTER.

EAC_LENGTH_BYTE: This 12-bit field indicates the length, in byte, of theEAC.

EAC_COUNTER: This 12-bit field indicates the number of the frames beforethe frame where the EAC arrives.

The following field appears only if the AUX_FLAG field is equal to ‘1’:

AUX_PRIVATE_DYN: This 48-bit field is reserved for future use forsignaling auxiliary streams. The meaning of this field depends on thevalue of AUX_(—) STREAM_(—) TYPE in the configurable PLS2-STAT.

CRC_32: A 32-bit error detection code, which is applied to the entirePLS2.

FIG. 16 illustrates a logical structure of a frame according to anembodiment of the present invention.

As above mentioned, the PLS, EAC, FIC, DPs, auxiliary streams and dummycells are mapped into the active carriers of the OFDM symbols in theframe. The PLS1 and PLS2 are first mapped into one or more FSS(s). Afterthat, EAC cells, if any, are mapped immediately following the PLS field,followed next by FIC cells, if any. The DPs are mapped next after thePLS or EAC, FIC, if any. Type 1 DPs follows first, and Type 2 DPs next.The details of a type of the DP will be described later. In some case,DPs may carry some special data for EAS or service signaling data. Theauxiliary stream or streams, if any, follow the DPs, which in turn arefollowed by dummy cells. Mapping them all together in the abovementioned order, i.e. PLS, EAC, FIC, DPs, auxiliary streams and dummydata cells exactly fill the cell capacity in the frame.

FIG. 17 illustrates PLS mapping according to an embodiment of thepresent invention.

PLS cells are mapped to the active carriers of FSS(s). Depending on thenumber of cells occupied by PLS, one or more symbols are designated asFSS(s), and the number of FSS(s) N_FSS is signaled by NUM_FSS in PLS1.The FSS is a special symbol for carrying PLS cells. Since robustness andlatency are critical issues in the PLS, the FSS(s) has higher density ofpilots allowing fast synchronization and frequency-only interpolationwithin the FSS.

PLS cells are mapped to active carriers of the NFSS FSS(s) in a top-downmanner as shown in an example in FIG. 17. The PLS1 cells are mappedfirst from the first cell of the first FSS in an increasing order of thecell index. The PLS2 cells follow immediately after the last cell of thePLS1 and mapping continues downward until the last cell index of thefirst FSS. If the total number of required PLS cells exceeds the numberof active carriers of one FSS, mapping proceeds to the next FSS andcontinues in exactly the same manner as the first FSS.

After PLS mapping is completed, DPs are carried next. If EAC, FIC orboth are present in the current frame, they are placed between PLS and“normal” DPs.

FIG. 18 illustrates EAC mapping according to an embodiment of thepresent invention.

EAC is a dedicated channel for carrying EAS messages and links to theDPs for EAS. EAS support is provided but EAC itself may or may not bepresent in every frame. EAC, if any, is mapped immediately after thePLS2 cells. EAC is not preceded by any of the FIC, DPs, auxiliarystreams or dummy cells other than the PLS cells. The procedure ofmapping the EAC cells is exactly the same as that of the PLS.

The EAC cells are mapped from the next cell of the PLS2 in increasingorder of the cell index as shown in the example in FIG. 18. Depending onthe EAS message size, EAC cells may occupy a few symbols, as shown inFIG. 18.

EAC cells follow immediately after the last cell of the PLS2, andmapping continues downward until the last cell index of the last FSS. Ifthe total number of required EAC cells exceeds the number of remainingactive carriers of the last FSS mapping proceeds to the next symbol andcontinues in exactly the same manner as FSS(s). The next symbol formapping in this case is the normal data symbol, which has more activecarriers than a FSS.

After EAC mapping is completed, the FIC is carried next, if any exists.If FIC is not transmitted (as signaled in the PLS2 field), DPs followimmediately after the last cell of the EAC.

FIG. 19 illustrates FIC mapping according to an embodiment of thepresent invention.

(a) shows an example mapping of FIC cell without EAC and (b) shows anexample mapping of FIC cell with EAC.

FIC is a dedicated channel for carrying cross-layer information toenable fast service acquisition and channel scanning. This informationprimarily includes channel binding information between DPs and theservices of each broadcaster. For fast scan, a receiver can decode FICand obtain information such as broadcaster ID, number of services, andBASE_DP_ID. For fast service acquisition, in addition to FIC, base DPcan be decoded using BASE_DP_ID. Other than the content it carries, abase DP is encoded and mapped to a frame in exactly the same way as anormal DP. Therefore, no additional description is required for a baseDP. The FIC data is generated and consumed in the Management Layer. Thecontent of FIC data is as described in the Management Layerspecification.

The FIC data is optional and the use of FIC is signaled by the FIC_FLAGparameter in the static part of the PLS2. If FIC is used, FIC_FLAG isset to ‘1’ and the signaling field for FIC is defined in the static partof PLS2. Signaled in this field are FIC_VERSION, and FIC_LENGTH_BYTE.FIC uses the same modulation, coding and time interleaving parameters asPLS2. FIC shares the same signaling parameters such as PLS2_MOD and PLS2FEC. FIC data, if any, is mapped immediately after PLS2 or EAC if any.FIC is not preceded by any normal DPs, auxiliary streams or dummy cells.The method of mapping FIC cells is exactly the same as that of EAC whichis again the same as PLS.

Without EAC after PLS, FIC cells are mapped from the next cell of thePLS2 in an increasing order of the cell index as shown in an example in(a). Depending on the FIC data size, FIC cells may be mapped over a fewsymbols, as shown in (b).

FIC cells follow immediately after the last cell of the PLS2, andmapping continues downward until the last cell index of the last FSS. Ifthe total number of required FIC cells exceeds the number of remainingactive carriers of the last FSS, mapping proceeds to the next symbol andcontinues in exactly the same manner as FSS(s). The next symbol formapping in this case is the normal data symbol which has more activecarriers than a FSS.

If EAS messages are transmitted in the current frame, EAC precedes FIC,and FIC cells are mapped from the next cell of the EAC in an increasingorder of the cell index as shown in (b).

After FIC mapping is completed, one or more DPs are mapped, followed byauxiliary streams, if any, and dummy cells.

FIG. 20 illustrates a type of DP according to an embodiment of thepresent invention.

shows type 1 DP and (b) shows type 2 DP.

After the preceding channels, i.e., PLS, EAC and FIC, are mapped, cellsof the DPs are mapped. A DP is categorized into one of two typesaccording to mapping method:

Type 1 DP: DP is mapped by TDM

Type 2 DP: DP is mapped by FDM

The type of DP is indicated by DP_TYPE field in the static part of PLS2.FIG. 20 illustrates the mapping orders of Type 1 DPs and Type 2 DPs.Type 1 DPs are first mapped in the increasing order of cell index, andthen after reaching the last cell index, the symbol index is increasedby one. Within the next symbol, the DP continues to be mapped in theincreasing order of cell index starting from p=0. With a number of DPsmapped together in one frame, each of the Type 1 DPs are grouped intime, similar to TDM multiplexing of DPs.

Type 2 DPs are first mapped in the increasing order of symbol index, andthen after reaching the last OFDM symbol of the frame, the cell indexincreases by one and the symbol index rolls back to the first availablesymbol and then increases from that symbol index. After mapping a numberof DPs together in one frame, each of the Type 2 DPs are grouped infrequency together, similar to FDM multiplexing of DPs.

Type 1 DPs and Type 2 DPs can coexist in a frame if needed with onerestriction; Type 1 DPs always precede Type 2 DPs. The total number ofOFDM cells carrying Type 1 and Type 2 DPs cannot exceed the total numberof OFDM cells available for transmission of DPs:

D _(DP1) +D _(DP2) ≦D _(DP)  [Equation 2]

where DDP1 is the number of OFDM cells occupied by Type 1 DPs, DDP2 isthe number of cells occupied by Type 2 DPs. Since PLS, EAC, FIC are allmapped in the same way as Type 1 DP, they all follow “Type 1 mappingrule”. Hence, overall, Type 1 mapping always precedes Type 2 mapping.

FIG. 21 illustrates DP mapping according to an embodiment of the presentinvention.

shows an addressing of OFDM cells for mapping type 1 DPs and (b) showsan addressing of OFDM cells for mapping for type 2 DPs.

Addressing of OFDM cells for mapping Type 1 DPs (0, . . . , DDP1-1) isdefined for the active data cells of Type 1 DPs. The addressing schemedefines the order in which the cells from the TIs for each of the Type 1DPs are allocated to the active data cells. It is also used to signalthe locations of the DPs in the dynamic part of the PLS2.

Without EAC and FIC, address 0 refers to the cell immediately followingthe last cell carrying PLS in the last FSS. If EAC is transmitted andFIC is not in the corresponding frame, address 0 refers to the cellimmediately following the last cell carrying EAC. If FIC is transmittedin the corresponding frame, address 0 refers to the cell immediatelyfollowing the last cell carrying FIC. Address 0 for Type 1 DPs can becalculated considering two different cases as shown in (a). In theexample in (a), PLS, EAC and FIC are assumed to be all transmitted.Extension to the cases where either or both of EAC and FIC are omittedis straightforward. If there are remaining cells in the FSS aftermapping all the cells up to FIC as shown on the left side of (a).

Addressing of OFDM cells for mapping Type 2 DPs (0, . . . , DDP2-1) isdefined for the active data cells of Type 2 DPs. The addressing schemedefines the order in which the cells from the TIs for each of the Type 2DPs are allocated to the active data cells. It is also used to signalthe locations of the DPs in the dynamic part of the PLS2.

Three slightly different cases are possible as shown in (b). For thefirst case shown on the left side of (b), cells in the last FSS areavailable for Type 2 DP mapping. For the second case shown in themiddle, FIC occupies cells of a normal symbol, but the number of FICcells on that symbol is not larger than CFSS. The third case, shown onthe right side in (b), is the same as the second case except that thenumber of FIC cells mapped on that symbol exceeds CFSS.

The extension to the case where Type 1 DP(s) precede Type 2 DP(s) isstraightforward since PLS, EAC and FIC follow the same “Type 1 mappingrule” as the Type 1 DP(s).

A data pipe unit (DPU) is a basic unit for allocating data cells to a DPin a frame.

A DPU is defined as a signaling unit for locating DPs in a frame. A CellMapper 7010 may map the cells produced by the TIs for each of the DPs. ATime interleaver 5050 outputs a series of TI-blocks and each TI-blockcomprises a variable number of XFECBLOCKs which is in turn composed of aset of cells. The number of cells in an XFECBLOCK, Ncells, is dependenton the FECBLOCK size, Nldpc, and the number of transmitted bits perconstellation symbol. A DPU is defined as the greatest common divisor ofall possible values of the number of cells in a XFECBLOCK, Ncells,supported in a given PHY profile. The length of a DPU in cells isdefined as LDPU. Since each PHY profile supports different combinationsof FECBLOCK size and a different number of bits per constellationsymbol, LDPU is defined on a PHY profile basis.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention before bit interleaving. As above mentioned, Data FECencoder may perform the FEC encoding on the input BBF to generateFECBLOCK procedure using outer coding (BCH), and inner coding (LDPC).The illustrated FEC structure corresponds to the FECBLOCK. Also, theFECBLOCK and the FEC structure have same value corresponding to a lengthof LDPC codeword.

The BCH encoding is applied to each BBF (Kbch bits), and then LDPCencoding is applied to BCH-encoded BBF (Kldpc bits=Nbch bits) asillustrated in FIG. 22.

The value of Nldpc is either 64800 bits (long FECBLOCK) or 16200 bits(short FECBLOCK).

The below table 28 and table 29 show FEC encoding parameters for a longFECBLOCK and a short FECBLOCK, respectively.

TABLE 28 BCH error LDPC correction Nbch − Rate Nldpc Kldpc Kbchcapability Kbch 5/15 64800 21600 21408 12 192 6/15 25920 25728 7/1530240 30048 8/15 34560 34368 9/15 38880 38688 10/15  43200 43008 11/15 47520 47328 12/15  51840 51648 13/15  56160 55968

TABLE 29 BCH error LDPC correction Nbch − Rate Nldpc Kldpc Kbchcapability Kbch 5/15 16200 5400 5232 12 168 6/15 6480 6312 7/15 75607392 8/15 8640 8472 9/15 9720 9552 10/15  10800 10632 11/15  11880 1171212/15  12960 12792 13/15  14040 13872

The details of operations of the BCH encoding and LDPC encoding are asfollows:

A 12-error correcting BCH code is used for outer encoding of the BBF.The BCH generator polynomial for short FECBLOCK and long FECBLOCK areobtained by multiplying together all polynomials.

LDPC code is used to encode the output of the outer BCH encoding. Togenerate a completed Bldpc (FECBLOCK), Pldpc (parity bits) is encodedsystematically from each Ildpc (BCH-encoded BBF), and appended to Ildpc.The completed Bldpc (FECBLOCK) are expressed as follow Equation.

B _(ldpc) [I _(ldpc) P _(ldpc) ][i ₀ ,i ₁ , . . . ,i _(K) _(ldpc) ₋₁ ,p₀ ,p ₁ , . . . ,p _(N) _(ldpc) _(-K) _(ldpc) ₋₁]  [Equation 3]

The parameters for long FECBLOCK and short FECBLOCK are given in theabove table 28 and 29, respectively.

The detailed procedure to calculate Nldpc−Kldpc parity bits for longFECBLOCK, is as follows:

-   -   1) Initialize the parity bits,

p ₀ =p ₁ =p ₂ = . . . =p _(N) _(ldpc) _(-K) _(ldpc) ₋₁=0  [Equation 4]

2) Accumulate the first information bit—i0, at parity bit addressesspecified in the first row of an addresses of parity check matrix. Thedetails of addresses of parity check matrix will be described later. Forexample, for rate 13/15:

$\begin{matrix}{{p_{983} = {p_{983} \oplus i_{0}}}{p_{2815} = {p_{2815} \oplus i_{0}}}{p_{4837} = {p_{4837} \oplus i_{0}}}{p_{4989} = {p_{4989} \oplus i_{0}}}{p_{6138} = {p_{6138} \oplus i_{0}}}{p_{6458} = {p_{6458} \oplus i_{0}}}{p_{6921} = {p_{6921} \oplus i_{0}}}{p_{6974} = {p_{6974} \oplus i_{0}}}{p_{7572} = {p_{7572} \oplus i_{0}}}{p_{8260} = {p_{8260} \oplus i_{0}}}{p_{8496} = {p_{8496} \oplus i_{0}}}} & \left\lbrack {{Equation}\mspace{14mu} 5} \right\rbrack\end{matrix}$

3) For the next 359 information bits, is, s=1, 2, . . . , 359 accumulateis at parity bit addresses using following Equation.

{x+(s mod 360)×Q _(ldpc)} mod(N _(ldpc) −K _(ldpc))  [Equation 6]

where x denotes the address of the parity bit accumulator correspondingto the first bit i0, and Qldpc is a code rate dependent constantspecified in the addresses of parity check matrix. Continuing with theexample, Qldpc=24 for rate 13/15, so for information bit i1, thefollowing operations are performed:

$\begin{matrix}{{p_{1007} = {p_{1007} \oplus i_{1}}}{p_{2839} = {p_{2839} \oplus i_{1}}}{p_{4861} = {p_{4861} \oplus i_{1}}}{p_{5013} = {p_{5013} \oplus i_{1}}}{p_{6162} = {p_{6162} \oplus i_{1}}}{p_{6482} = {p_{6482} \oplus i_{1}}}{p_{6945} = {p_{6945} \oplus i_{1}}}{p_{6998} = {p_{6998} \oplus i_{1}}}{p_{7596} = {p_{7596} \oplus i_{1}}}{p_{8284} = {p_{8284} \oplus i_{1}}}{p_{8520} = {p_{8520} \oplus i_{1}}}} & \left\lbrack {{Equation}\mspace{14mu} 7} \right\rbrack\end{matrix}$

4) For the 361st information bit i360, the addresses of the parity bitaccumulators are given in the second row of the addresses of paritycheck matrix. In a similar manner the addresses of the parity bitaccumulators for the following 359 information bits is, s=361, 362, . .. , 719 are obtained using the Equation 6, where x denotes the addressof the parity bit accumulator corresponding to the information bit i360,i.e., the entries in the second row of the addresses of parity checkmatrix.

5) In a similar manner, for every group of 360 new information bits, anew row from addresses of parity check matrixes used to find theaddresses of the parity bit accumulators.

After all of the information bits are exhausted, the final parity bitsare obtained as follows:

6) Sequentially perform the following operations starting with i=1

p _(i) =p _(i) ⊕p _(i-1) ,i=1,2, . . . ,N _(ldpc) −K_(ldpc)−1  [Equation 8]

where final content of pi, i=0, 1, . . . Nldpc−Kldpc−1 is equal to theparity bit pi.

TABLE 30 Code Rate Qldpc 5/15 120 6/15 108 7/15 96 8/15 84 9/15 7210/15  60 11/15  48 12/15  36 13/15  24

This LDPC encoding procedure for a short FECBLOCK is in accordance witht LDPC encoding procedure for the long FECBLOCK, except replacing thetable 30 with table 31, and replacing the addresses of parity checkmatrix for the long FECBLOCK with the addresses of parity check matrixfor the short FECBLOCK.

TABLE 31 Code Rate Qldpc 5/15 30 6/15 27 7/15 24 8/15 21 9/15 18 10/15 15 11/15  12 12/15  9 13/15  6

FIG. 23 illustrates a bit interleaving according to an embodiment of thepresent invention.

The outputs of the LDPC encoder are bit-interleaved, which consists ofparity interleaving followed by Quasi-Cyclic Block (QCB) interleavingand inner-group interleaving.

shows Quasi-Cyclic Block (QCB) interleaving and (b) shows inner-groupinterleaving.

The FECBLOCK may be parity interleaved. At the output of the parityinterleaving, the LDPC codeword consists of 180 adjacent QC blocks in along FECBLOCK and 45 adjacent QC blocks in a short FECBLOCK. Each QCblock in either a long or short FECBLOCK consists of 360 bits. Theparity interleaved LDPC codeword is interleaved by QCB interleaving. Theunit of QCB interleaving is a QC block. The QC blocks at the output ofparity interleaving are permutated by QCB interleaving as illustrated inFIG. 23, where Ncells=64800/η mod or 16200/η mod according to theFECBLOCK length. The QCB interleaving pattern is unique to eachcombination of modulation type and LDPC code rate.

After QCB interleaving, inner-group interleaving is performed accordingto modulation type and order (η mod) which is defined in the below table32. The number of QC blocks for one inner-group, NQC_IG, is alsodefined.

TABLE 32 Modulation type ηmod NQCB_IG QAM-16 4 2 NUC-16 4 4 NUQ-64 6 3NUC-64 6 6 NUQ-256 8 4 NUC-256 8 8 NUQ-1024 10 5 NUC-1024 10 10

The inner-group interleaving process is performed with NQCB_IG QC blocksof the QCB interleaving output. Inner-group interleaving has a processof writing and reading the bits of the inner-group using 360 columns andNQCB_IG rows. In the write operation, the bits from the QCB interleavingoutput are written row-wise. The read operation is performed column-wiseto read out m bits from each row, where m is equal to 1 for NUC and 2for NUQ.

FIG. 24 illustrates a cell-word demultiplexing according to anembodiment of the present invention.

shows a cell-word demultiplexing for 8 and 12 bpcu MIMO and (b) shows acell-word demultiplexing for 10 bpcu MIMO.

Each cell word (c0,l, c1,l, . . . , cη mod−1,l) of the bit interleavingoutput is demultiplexed into (d1,0,m, d1,1,m . . . , d1,η mod−1,m) and(d2,0,m, d2,1,m . . . , d2,η mod−1,m) as shown in (a), which describesthe cell-word demultiplexing process for one XFECBLOCK.

For the 10 bpcu MIMO case using different types of NUQ for MIMOencoding, the Bit Interleaver for NUQ-1024 is re-used. Each cell word(c0,l, c1,l, . . . , c9,l) of the Bit Interleaver output isdemultiplexed into (d1,0,m, d1,1,m . . . , d1,3,m) and (d2,0,m, d2,1,m .. . , d2,5,m), as shown in (b).

FIG. 25 illustrates a time interleaving according to an embodiment ofthe present invention.

(a) to (c) show examples of TI mode.

The time interleaver operates at the DP level. The parameters of timeinterleaving (TI) may be set differently for each DP.

The following parameters, which appear in part of the PLS2-STAT data,configure the TI:

DP_TI_TYPE (allowed values: 0 or 1): Represents the TI mode; ‘0’indicates the mode with multiple TI blocks (more than one TI block) perTI group. In this case, one TI group is directly mapped to one frame (nointer-frame interleaving). ‘1’ indicates the mode with only one TI blockper TI group. In this case, the TI block may be spread over more thanone frame (inter-frame interleaving).

DP_TI_LENGTH: If DP_TI_TYPE=‘0’, this parameter is the number of TIblocks NTI per TI group. For DP_TI_TYPE=‘1’, this parameter is thenumber of frames PI spread from one TI group.

DP_NUM_BLOCK_MAX (allowed values: 0 to 1023): Represents the maximumnumber of XFECBLOCKs per TI group.

DP_FRAME_INTERVAL (allowed values: 1, 2, 4, 8): Represents the number ofthe frames IJUMP between two successive frames carrying the same DP of agiven PHY profile.

DP_TI_BYPASS (allowed values: 0 or 1): If time interleaving is not usedfor a DP, this parameter is set to ‘1’. It is set to ‘0’ if timeinterleaving is used.

Additionally, the parameter DP_NUM_BLOCK from the PLS2-DYN data is usedto represent the number of XFECBLOCKs carried by one TI group of the DP.

When time interleaving is not used for a DP, the following TI group,time interleaving operation, and TI mode are not considered. However,the Delay Compensation block for the dynamic configuration informationfrom the scheduler will still be required. In each DP, the XFECBLOCKsreceived from the SSD/MIMO encoding are grouped into TI groups. That is,each TI group is a set of an integer number of XFECBLOCKs and willcontain a dynamically variable number of XFECBLOCKs. The number ofXFECBLOCKs in the TI group of index n is denoted by NxBLOCK_Group(n) andis signaled as DP_NUM_BLOCK in the PLS2-DYN data. Note thatNxBLOCK_Group(n) may vary from the minimum value of 0 to the maximumvalue NxBLOCK_Group_MAX (corresponding to DP_NUM_BLOCK_MAX) of which thelargest value is 1023.

Each TI group is either mapped directly onto one frame or spread over PIframes. Each TI group is also divided into more than one TI blocks(NTI), where each TI block corresponds to one usage of time interleavermemory. The TI blocks within the TI group may contain slightly differentnumbers of XFECBLOCKs. If the TI group is divided into multiple TIblocks, it is directly mapped to only one frame. There are three optionsfor time interleaving (except the extra option of skipping the timeinterleaving) as shown in the below table 33.

TABLE 33 Mode Description Option-1 Each TI group contains one TI blockand is mapped directly to one frame as shown in (a). This option issignaled in the PLS2-STAT by DP_TI_TYPE = ‘0’ and DP_TI_LENGTH =‘1’(N_(TI) = 1). Option-2 Each TI group contains one TI block and ismapped to more than one frame. (b) shows an example, where one TI groupis mapped to two frames, i.e., DP_TI_LENGTH = ‘2’ (P_(I) = 2) andDP_FRAME_INTERVAL (I_(JUMP) = 2). This provides greater time diversityfor low data-rate services. This option is signaled in the PLS2-STAT byDP_TI_TYPE = ‘1’. Option-3 Each TI group is divided into multiple TIblocks and is mapped directly to one frame as shown in (c). Each TIblock may use full TI memory, so as to provide the maximum bit-rate fora DP. This option is signaled in the PLS2-STAT signaling by DP_TI_TYPE =‘0’ and DP_TI_LENGTH = NTI, while P_(I) = 1.

In each DP, the TI memory stores the input XFECBLOCKs (output XFECBLOCKsfrom the SSD/MIMO encoding block). Assume that input XFECBLOCKs aredefined as

(d_(n, s, 0, 0), d_(n, s, 0, 1), …, d_(n, s, 0, N_(cells) − 1), d_(n, s, 1, 0), …, d_(n, s, 1, N_(cells) − 1), …, d_(n, s, N_(xBLOCK_(—)TI)(n, s) − 1, 0), …, d_(n, s, N_(xBLOCK_(—)TI)(n, s) − 1, N_(cells) − 1)),

where d_(n,s,r,q) is the qth cell of the rth XFECBLOCK in the sth TIblock of the nth TI group and represents the outputs of SSD and MIMOencodings as follows

$d_{n,s,r,q} = \left\{ {\begin{matrix}{f_{n,s,r,q}.} & {{{the}\mspace{14mu} {output}\mspace{14mu} {of}\mspace{14mu} {SSD\cdots}\; {encoding}}\mspace{11mu}} \\{g_{n,s,r,q},} & {{the}\mspace{14mu} {output}\mspace{14mu} {of}\mspace{14mu} {MIMO}\mspace{14mu} {encoding}}\end{matrix}.} \right.$

In addition, assume that output XFECBLOCKs from the time interleaver5050 are defined as

(h_(n, s, 0), h_(n, s, 1), …, h_(n, s, i), …, h_(n, s, N_(xBLOCK_(—)TI)(n, s) × N_(cells) − 1)),

where h_(n,s,i) is the ith output cell (for i=0, . . . , N_(xBLOCK) _(_)_(TI)(n,s)×N_(cells)−1) in the sth TI block of the nth TI group.

Typically, the time interleaver will also act as a buffer for DP dataprior to the process of frame building. This is achieved by means of twomemory banks for each DP. The first TI-block is written to the firstbank. The second TI-block is written to the second bank while the firstbank is being read from and so on.

The TI is a twisted row-column block interleaver. For the sth TI blockof the nth TI group, the number of rows N_(r) of a TI memory is equal tothe number of cells N_(cells), i.e., N_(r)=N_(cells) while the number ofcolumns N_(c) is equal to the number N_(xBLOCK) _(_) _(TI)(n,s).

FIG. 26 illustrates a basic operation of a twisted row-column blockinterleaver according to an exemplary embodiment of the presentinvention.

FIG. 26A illustrates a writing operation in a time interleaver and FIG.26B illustrates a reading operation in the time interleaver. Asillustrated in FIG. 26A, a first XFECBLOCK is written in a first columnof a time interleaving memory in a column direction and a secondXFECBLOCK is written in a next column, and such an operation iscontinued. In addition, in an interleaving array, a cell is read in adiagonal direction. As illustrated in FIG. 26B, while the diagonalreading is in progress from a first row (to a right side along the rowstarting from a leftmost column) to a last row, N_(r) cells are read. Indetail, when it is assumed that z_(n,s,i)(i=0, . . . , N_(r)N_(c)) is atime interleaving memory cell position to be sequentially read, thereading operation in the interleaving array is executed by calculating arow index R_(n,s,i), a column index C_(n,s,i), and associated twistparameter T_(n,s,i) as shown in an equation given below.

$\begin{matrix}{{{GENERATE}\left( {R_{n,s,i},C_{n,s,i}} \right)} = \left\{ {{R_{n,s,i} = {{mod}\left( {i,N_{r}} \right)}},{T_{n,s,i} = {{mod}\left( {{S_{shift} \times R_{n,s,i}},N_{c}} \right)}},{C_{n,s,i} = {{mod}\left( {{T_{n,s,i} + \left\lfloor \frac{i}{N_{r}} \right\rfloor},N_{c}} \right)}}} \right\}} & \left\lbrack {{Equation}\mspace{14mu} 9} \right\rbrack\end{matrix}$

Where, S_(shift) is a common shift value for a diagonal reading processregardless of N_(xBLOCK) _(_) _(TI)(n,s) and the shift value is decidedby N_(xBLOCK) _(_) _(TI) _(_) _(MAX) given in PLS2-STAT as shown in anequation given below.

$\begin{matrix}{{for}\left\{ {\begin{matrix}{{N_{{xBLOCK}_{—}{TI}_{—}{MAX}}^{\prime} = {N_{{xBLOCK}_{—}{TI}_{—}{MAX}} + 1}},} & {{{if}\mspace{14mu} N_{{xBLOCK}_{—}{TI}_{—}{MAX}}{mod}\; 2} = 0} \\{{N_{{xBLOCK}_{—}{TI}_{—}{MAX}}^{\prime} = N_{{xBLOCK}_{—}{TI}_{—}{MAX}}},} & {{{if}\mspace{14mu} N_{{xBLOCK}_{—}{TI}_{—}{MAX}}{mod}\; 2} = 1}\end{matrix},{S_{shift} = \frac{N_{{xBLOCK}_{—}{TI}_{—}{MAX}}^{\prime} - 1}{2}}} \right.} & \left\lbrack {{Equation}\mspace{14mu} 10} \right\rbrack\end{matrix}$

Consequently, the cell position to be read is calculated by a coordinatez_(n,s,i)=N_(r)C_(n,s,i)+R_(n,s,i).

FIG. 27 illustrates an operation of a twisted row-column blockinterleaver according to another exemplary embodiment of the presentinvention.

In more detail, FIG. 27 illustrates an interleaving array in the timeinterleaving memory for respective time interleaving groups including avirtual XFECBLOCK when N_(xBLOCK) _(_) _(TI)(0,0)=3, N_(xBLOCK) _(_)_(TI)(1,0)=6, and N_(xBLOCK) _(_) _(TI)(2,0)=5.

A variable N_(xBLOCK) _(_) _(TI)(n,s)=N_(r), will be equal to or smallerthan N′_(xBLOCK) _(_) _(TI) _(_) _(MAX). Accordingly, in order for areceiver to) achieve single memory interleaving regardless of N_(xBLOCK)_(_) _(TI)(n,s) the size of the interleaving array for the twistedrow-column block interleaver is set to a size ofN_(r)×N_(c)=N_(cells)×N′_(xBLOCK) _(_) _(TI) _(_) _(MAX) by insertingthe virtual XFECBLOCK into the time interleaving memory and a readingprocess is achieved as shown in an equation given below.

[Equation 11] p = 0; for i = 0; i < N_(cells)N′_(xBLOCK) _(—) _(TI) _(—)_(MAX); i = i + 1 {GENERATE (R_(n,s,i), C_(n,s,i)); V_(i) =N_(r)C_(n,s,j) + R_(n,s,j)  if V_(i) < N_(cells)N_(xBLOCK TI)(n,s)  {Z_(n,s,p) = V_(i); p = p + 1; } }

The number of the time interleaving groups is set to 3. An option of thetime interleaver is signaled in the PLS2-STAT by DP_TI_TYPE=‘0’,DP_FRAME_INTERVAL=‘1’, and DP_TI_LENGTH=‘1’, that is, NTI=1, IJUMP=1,and PI=1. The number of respective XFECBLOCKs per time interleavinggroup, of which Ncells=30 is signaled in PLS2-DYN data byNxBLOCK_TI(0,0)=3, NxBLOCK_TI(1,0)=6, and NxBLOCK_TI(2,0)=5 of therespective XFECBLOCKs. The maximum number of XFECBLOCKs is signaled inthe PLS2-STAT data by NxBLOCK_Group_MAX and this is continued to└N_(xBLOCK) _(_) _(Group) _(_) _(MAX)/N_(TI)┘=N_(xBLOCK) _(_) _(TI) _(_)_(MAX)=6.

FIG. 28 illustrates a diagonal reading pattern of the twisted row-columnblock interleaver according to the exemplary embodiment of the presentinvention.

In more detail, FIG. 28 illustrates a diagonal reading pattern fromrespective interleaving arrays having parameters N′_(xBLOCK) _(_) _(TI)_(_) _(MAX)=7 and Sshift=(7−1)/2=3. In this case, during a readingprocess expressed by a pseudo code given above, whenV_(i)≧N_(cells)N_(xBLOCK) _(_) _(TI)(n,s), a value of Vi is omitted anda next calculation value of Vi is used.

FIG. 29 illustrates XFECBLOCK interleaved from each interleaving arrayaccording to an exemplary embodiment of the present invention.

FIG. 29 illustrates XFECBLOCK interleaved from each interleaving arrayhaving parameters N′_(xBLOCK) _(_) _(TI) _(_) _(MAX)=7 and Sshift=3according to an exemplary embodiment of the present invention.

In this specification, the DP may also be designated as a Physical LayerPipe (PLP), and the PLS information may also be designated as Layer 1(L1) information or L1 signaling information. The PLS1 information mayalso be designated as Layer 1 (L1) static information or Layer 1 (L1)basic information, and the PLS2 information may also be designated asL1-dynamic information or L1 detail information. In this specification,if specific information/data is signaled, it may mean that theinformation/data is transmitted and received through the L1 signalinginformation.

FIG. 30 shows the configuration of a broadcast signal transmitteraccording to another embodiment of the present invention.

The broadcast signal transmitter of FIG. 30 may include an inputformatting block 30010, a Bit Interleaved and Coded Modulation (BICM)block 30020, a framing & interleaving block 30030, and a waveformgeneration block 30040. The framing & interleaving block 30030 of FIG.30 may correspond to the frame building block of FIG. 1, and thewaveform generation block 30040 thereof may correspond to the OFDMgeneration block of FIG. 1.

FIG. 30 corresponds to a case where the frame building block 1020includes the time interleaving block 30050 unlike in the aforementionedembodiments. Accordingly, the frame building block 1020 may be calledthe framing & interleaving block 30050. In other words, the framing &interleaving block 30030 may further include a time interleaving block30050, a framing block 30060, and a frequency interleaving block 30070.The framing & interleaving block 30030 may time-interleave data usingsuch sub-blocks, may generate a signal frame by mapping the data, andmay frequency-interleave the signal frame.

The remaining description other than a case where the time interleavingblock 30050 has moved from the BICM block 30020 to the framing &interleaving block 30030 is the same as that described above. Thewaveform generation block 30040 is the same as the OFDM generation block1030 of FIG. 1 and is different in name only.

On the broadcast signal receiver side, as described above, the timeinterleaving block has moved from the demapping and decoding block 9020of FIG. 9 to the frame parsing block 9010, and the frame parsing block9010 may also be designated as a frame parsing/deinterleaving block. Theframe parsing block 9010 may performs frequency deinterleaving, frameparsing, and time interleaving on a received signal.

In FIG. 30, only the inclusion relationships between the sub-blocks ofthe system are changed and the sub-blocks are renamed, and detailedoperations of the sub-blocks are the same as those described above. Inthis specification, as in the previous embodiments, the elements of thetransmission and reception system may also be designated blocks,modules, or units.

In FIG. 30, the framing module 31060 generates a signal frame. A methodof configuring a signal frame according to an embodiment of the presentinvention is described in more detail below.

FIG. 31 shows the pilot structure of a signal frame according to anembodiment of the present invention.

As in FIG. 31, the actual bandwidth of the signal frame may varydepending on the Number of Carriers (NoC).

The signal frame includes Edge Pilots (EPs), Continual Pilots (CPs), andScattered Pilots (SPs).

The EP or edge carrier indicates carriers whose carrier index kcorresponds to 0 or NoC−1.

A Continual Pilot (CP) is inserted into every the symbols of a signalframe. The frequency direction index of the CP is determined to be aspecific pattern depending on an FFT size. The CP includes a common CPand an additional CP. The common CP corresponds to a non-SP-bearing-CP,and the additional CP corresponds to an SP-bearing-CP. The additional CPis added in order to maintain constant number of data carriers per datasymbol. That is, the additional CP is added in order to ensure theconstant Number of Active carriers (NoA) per symbol.

A Scattered Pilot (SP) is disposed depending on an SP pattern indicatedby Dx and Dy. Dx indicates the distance or separation of pilot-bearingcarriers in a frequency direction. Dy indicates the number of symbolsforming a single SP sequence in a time direction. For example, in FIG.31, an SP pattern is Dx=4 and Dy=4. An SP pattern used in a subframe maybe transmitted using the L1 signaling information of a preamble.

An actual occupied bandwidth of a transmission signal frame may becontrolled depending on the NoC as in FIG. 31. That is, an actualoccupied bandwidth of a signal frame may be controlled by flexiblycontrolling the NoC, and a parameter regarding the NoC may be signaled.The NoC may be defined as in Equation 12.

NoC=NoC _(max) −C _(red) _(_) _(coeff) *C _(unit)  [Equation 12]

In Equation 12, NoC_max denotes a maximum number of carriers per symbol.C_red_coeff is a positive integer, and denotes a coefficient which ismultiplied by a control unit value “C_unit” and which determines thereduced number of carriers. C_red_doeff may also be designated as an NoCreduction coefficient. C_red_coeff has a value of 0˜4, which may besignaled as parameters. The parameters may be signaled as the NoCreduction coefficient of each preamble “L1B_preamble_reduced_carriers”,the NoC reduction coefficient of a first subcarrier“L1B_First_Sub_reduced_carriers”, and the NoC reduction coefficient ofsubcarriers subsequent to a second subcarrier “L1D_reduced_carriers.”The control unit value “C_unit” has a maximum Dx value. In other words,the control unit value is determined to be a maximum Dx valuecorresponding to the least common multiple of a Dx value having a basisof 3 and a Dx value having a basis of 4. The control unit value may bedetermined to be 96 with respect to 8K FFT, 192 with respect to 16K FFT,and 384 with respect to 32K FFT.

Table 34 below shows NoCs determined by Equation 12 with respect to FFTsizes and C_red_coeff.

TABLE 34 NoC C_red_coeff 8K FFT 16K FFT 32K FFT 0 6913 13825 27649 16817 13633 27265 2 6721 13441 26881 3 6625 13249 26497 4 6529 1305726113

In Table 34, the NoC when C_red_coeff=0 corresponds to theaforementioned NoC_max. 0˜4, that is, the values of C_red_coeff, may besignaled using 3 bits. Hereinafter, the values of 0˜4 may be indicatedby 000, 001, 010, 011, and 100, respectively. Furthermore, the NoC whenan NoC reduction coefficient “C_red_coeff” is 4 corresponds to a minimumNoC “NoC_min.” The broadcast system according to an embodiment of thepresent invention may signal the NoC of a signal frame by sending theNoC reduction coefficient “C_red_coeff” in a preamble. The broadcastsignal receiver may receive the NoC reduction coefficient and may beaware of a corresponding FFT size based on Table 34. A signaled NoCreduction coefficient may also be called NoC-related information.

FIG. 32 shows the structure of a signal frame according to an embodimentof the present invention.

The signal frame may include a bootstrap, a preamble, and a data part.

A bootstrap signal may be robustly designed in such a way as to operatein a poor channel environment. The bootstrap signal may send essentialsystem information and essential information capable of accessing acorresponding broadcast system.

The bootstrap signal may be used in the locking and offset estimation ofan RF carrier frequency and the locking and offset estimation of asampling frequency. The bootstrap signal may signal system bandwidthinformation (e.g., 6, 7, 8 MHz). Furthermore, the bootstrap signal mayinclude core system signaling information (e.g., major/minor versioninformation). Furthermore, the bootstrap information may signal the timeuntil the start of a next data frame. Furthermore, the bootstrapinformation may carry the identifiers of L1 signaling informationtransmitted in the preamble. Furthermore, the bootstrap signal maysupport an Emergency Alert System (EAS) wakeup function. The EAS wakeupinformation of the bootstrap signal may indicate whether an emergencysituation has occurred. That is, the EAS information may indicatewhether emergency alert information from an EAS or another source ispresent in at least one frame.

The bootstrap includes preamble structure information. The preamblestructure information may indicate L1-basic mode information,information about the FFT size of the preamble, information about the GIlength of the preamble, and information about the pilot pattern Dx ofthe preamble.

FIG. 33 shows the structure of a signal frame according to anotherembodiment of the present invention.

In FIG. 33, the preamble of the signal frame includes L1-fixed,L1-static, and L1-dynamic. The L1-fixed, L1-static, and L1-dynamic mayalso be called L1-fixed signaling information, L1-static signalinginformation, and L1-dynamic signaling information, respectively.

The preamble carries L1 signaling information so that a serviceindicated by a bootstrap and provided by a system can be obtained. TheL1 signaling information includes information corresponding to adetailed frame structure and information on which service data withinthe signal frame is able to be accessed. The L1 signaling informationmay carry modulation/coding (ModCod) mode and information about aposition within the signal frame by comprehensively taking intoconsideration the robustness requirements and decoding latency of thesystem. In this specification, modulation/coding (ModCod) informationindicates a combination of modulation and coding rates for determiningthe size of a baseband packet.

In an embodiment, the L1-fixed field may carry ModCod information of L1signaling and information about a position within the frame. Informationabout a modulation/coding scheme, position, and field size of theL1-fixed field itself may be fixed according to a corresponding system.L1 signaling fields subsequent to the L1-fixed field may be decodedusing the modulation/coding scheme, position, and field size transmittedin the L1-fixed field.

The L1 signaling fields subsequent to the L1-fixed field may include theL1-static field and the L1-dynamic field. The L1-static field hasvariable modulation/coding mode and corresponds to a static signalingfield which does not vary with respect to a corresponding super frame ora plurality of PLPs. The L1-dynamic field has variable modulation/codingmode and corresponds to a dynamic signaling field which is variable foreach frame (e.g., for each PLP size and position). An additional gain ofrobustness of the L1-static field may be obtained using a repetitioncharacteristic. The L1-dynamic field may be additionally transmittedthrough in-band signaling.

FIG. 34 shows the structure of a signal frame according to anotherembodiment of the present invention.

In the case of FIG. 34, a preamble symbol carries L1-static signalingdata and L1-dynamic signaling data.

In order to simplify the operation of the broadcast signal receiver andto efficiently send L1 signaling information, L1 modulation/coding(ModCod) information, a location, and field length information may betransmitted in a bootstrap. In this case, the L1-fixed field of FIG. 33does not need to be used. Accordingly, system operation efficiency canbe improved because the location of L1 signaling and a modulation/codingscheme (Mod/Cod) can be flexibly changed in association with therobustness and characteristic of service data within a signal frame.

Essential information forming physical layer parameters transmitted in abootstrap and a preamble may also be called L1 signaling or L1 signalinginformation.

FIG. 35 shows the structure of a signal frame according to anotherembodiment of the present invention.

FIG. 35 shows the signal frame of FIG. 34 by symbol. Each of thepreamble and data of the signal frame may include at least one symbol.

The preamble conveys L1 signaling information. Furthermore, the preamblemay include a single OFDM symbol or a plurality of OFDM symbolsdepending on the size of the L1 signaling information, that is, thenumber of bits. The preamble may have the same structure (e.g., an FFTsize and a Guard Interval (GI)) as the data symbol. In this case, thestructure of the preamble symbol or the data symbol may be signaled inthe bootstrap. That is, the bootstrap may also indicate an FFT size, GIlength, and pilot pattern of the preamble. Furthermore, the bootstrapmay send modulation/coding (ModCod) information, position information,and field size information of the preamble.

Advantages if information about the preamble/data part is transmitted inthe bootstrap are as follows. The operation of the broadcast signalreceiver can be simplified. Furthermore, a service acquisition timeincluding a channel scan can be reduced because the time taken to obtainL1 signaling information is reduced. Furthermore, reception performancecan be improved because an FFT/GI false detection possibility is reducedin a poor channel situation.

A single signal frame may include at least one subframe. Furthermore,one of 8K, 16K, and 32K may be used as the FFT size of each subframe,and the FFT size of each subframe may be the same or different. Thesubframe has a fixed FFT size, GI length, Scattered Pilot (SP) pattern,and Number Of useful Carriers (NoC) for the corresponding subframe.Furthermore, FFT size information, GI length information, pilot patterninformation, and NoC information about a corresponding subframe may beincluded in a preamble and transmitted/received.

The number of OFDM symbols may be determined by the number of signalingbits. Furthermore, the number of preamble symbols may betransmitted/received in the L1-static field. The preamble structure maybe signaled in the bootstrap. Furthermore, the bootstrap may not includeNoC information because a minimum NoC is used in the first preamblesymbol.

FIG. 36 shows the structure of a signal frame according to anotherembodiment of the present invention.

As in FIG. 36, the structure of a preamble may be separately configuredand fixed like a bootstrap without being configured identically with adata symbol structure. The structure of the preamble may be configuredto have the most robust structure by taking into consideration variousstructures and change possibilities of a data symbol. In a broadcastingsystem, in the case of an OFDM method, a preamble may be designed tohave the smallest FFT size and a maximum (Max) GI supported by thesystem. For example, if a broadcasting system supports 8K, 16K, and 32KFFT sizes and the Max GI supports 4864 samples with respect to the 32KFFT size, the FFT size and GI of a preamble symbol may be set to 8K and4864 samples, respectively.

If a preamble structure is fixed as described above, signaling overheadcan be reduced because bootstrap signaling is not required, and the sameperformance can be provided in structure from a viewpoint of a Dopplerand coverage.

FIG. 37 shows the structure of a signal frame according to anotherembodiment of the present invention.

FIG. 37 shows an embodiment in which only the first preamble symbol ofpreambles is configured to have a fixed structure and structures aresignaled with respect to the remaining preambles. If the most robuststructure is fixed with respect to all of preamble symbols as in FIG.36, system performance is deteriorated because the amount of datatransfer is not increased even in a good channel situation. IF all thepreambles are set to 8K FFT and GI=4864, overhead is too great.Accordingly, in a broadcasting system, only the structure of the firstpreamble may be fixed and the remaining preambles may be configuredaccording to the structure of a data symbol by comprising a method forfixing a preamble structure and a method of signaling a preamblestructure. In this case, the structure of preamble symbols subsequent tothe second preamble symbol may be signaled using the first preamblesymbol.

A method of signaling a preamble structure in a bootstrap is describedbelow.

The FFT size, Guard Interval (GI), pilot pattern, and NoC of a preamblestructure need to be defined. Furthermore, whether L1 signaling FEC,Layered Division Multiplexing (LDM), and/or SISO/MIMO method is used maybe additionally taken into consideration.

In the case of an FFT size and a GI, a broadcasting system needs tosupport a maximum GI for each FFT size, and the support of a finer GImay reduce preamble overhead.

The pilot pattern of a preamble may be defined using Dy=1 and a Dxvalue. In this case, since pilot density of preamble symbols isincreased, the role of an edge symbol can be performed and a preamblecan be rapidly obtained. In an embodiment, two types of GI mode may beprovided by providing a Dx basis 3 or 4 as Dx with respect to each pieceof FFT mode.

In the case of the NoC, the first preamble symbol may have a minimumNoC. Accordingly, in a bootstrap, the NoC of the first preamble symboldoes not need to be signaled. Additional preamble symbols may have thesame NoC as data symbols. NoC-related information about the data symbolsmay be carried in the L1-static information.

Preamble structure information carried in the bootstrap is described inmore detail below.

FIG. 38 shows a preamble structure indicator according to an embodimentof the present invention.

A preamble structure indicator may also be called preamble structureinformation. The first 3 bits of the preamble structure information mayindicate modulation/coding (Mod/Cod) information about a preamble. Inthe embodiment of FIG. 38, the preamble structure information mayrepresent 7 modulation/code combinations having different types ofAdditive White Gaussian Noise (AWGN) target SNR performance using 3bits. A detailed embodiment of modulation/coding mode of a preamble isshown in FIG. 48.

FIG. 39 shows a preamble structure indicator according to anotherembodiment of the present invention.

In an embodiment, the preamble structure information may include a totalof 6 bits, and the first 3 bits of the bits may indicatemodulation/coding mode as in the embodiment of FIG. 38. Furthermore, theremaining 3 bits of the 6 bits may indicate a combination of an FFTsize, GI sample number, and pilot separation as shown in FIG. 39.

In addition to modulation/coding mode, the preamble structure indicatorneeds to send FFT/GI/pilot pattern information. In general, a preambleis designed to be more robust than a data symbol, and thus the preambleneeds to be designed to enable robust synchronization and channelestimation. Furthermore, the preamble can reduce system overhead by alsofunctioning as an edge symbol (a subframe boundary symbol) because it isplaced at the boundary of a bootstrap signal and a data symbol. In orderfor the preamble to function as an edge symbol, the pilot separation ofthe preamble needs to be the submultiple of Dx or Dy of the pilotpattern of a data symbol. If the pilot separation of a preamble has theDx basis value of a data symbol, the preamble may function as an edgesymbol with respect to all data symbols having the same Dx basis. In thecase of a broadcast system according to an embodiment of the presentinvention, 3 and 4 may be used as a Dx basis. Accordingly, in order fora preamble to function as an edge symbol, the pilot separation of thepreamble needs to be designed to have the Dx value of the pilot patternof data symbols subsequent to the preamble or to have the value of thecommon denominator of Dx. Furthermore, information corresponding to thesubmultiple of Dx or Dy needs to be included in a bootstrap andtransmitted.

If 6 bits are assigned to the preamble structure information, the 3 bitsof the 6 bits are used to send ModCod information. The remaining 3 bitsof the 6 bits may indicate an FFT size, a GI sample number, and a pilotseparation as in the table of FIG. 39 so that a preamble functioning asan edge symbol can be coded.

In the example of an 8K FFT preamble, if subsequent data symbols have apilot pattern of a Dx basis 3 (corresponding to a GI #3/5/7), thepreamble is configured to have 8K FFT, 2048 GI samples, and a pilotseparation of 3, and a preamble structure indicator is set to a value of“000”. In an example of a K FFT preamble, if subsequent data symbolshave a pilot pattern of a Dx basis 4 (corresponding to a GI #1/2/46),the preamble is configured to have 8K FFT, 1536 GI samples, and a pilotseparation of 4, and a preamble structure indicator is set to a value of“001”. The GI # is described later.

A Dx basis 3 or 4 may be used for each FFT size, and the last two bitvalues “110” and “111” may be used for reserved values or may beallocated to reduce preamble overhead as described above.

FIG. 40 shows a preamble structure indicator according to anotherembodiment of the present invention.

In an embodiment, the preamble structure information may include a totalof 7 bits, and the first 3 bits of the 7 bits may indicate amodulation/coding scheme as in the embodiment of FIG. 38. Furthermore,the remaining 4 bits of the 7 bits may indicate an FFT size, GI samples,and a pilot distance/separation as shown in FIG. 40. In this case,system overhead can be generally reduced.

The disposition of the pilots of a preamble may have a Dx basis, same asthe SP of data symbols. Furthermore, the SP position of the preamble mayinclude the SP-bearing position of a data symbol. Accordingly, thepreamble may function as an edge symbol.

In order to reduce system overhead, a representative value may beselected for each Dx between 768 GI sample values in a Max GI samplevalue of each FFT size and used as a preamble GI. In this case, thegreatest GI sample value of GI sample values having the same Dx valuemay be used as the representative value of each Dx.

In addition, although not shown, 5 bits may be assigned in order to sendpreamble FFT/GI/SP information. In this case, in a broadcast systemaccording to an embodiment of the present invention, a total of types of30 FFT/GI/Dx, including 7 types for an 8K FFT size, 11 types for a 16KFFT size, and 12 types for a 32K FFT size, may be signaled using 5 bits.In this case, this may be most advantageous in terms of preambleoverhead because accurate Dx value and GI can be designated.

FIG. 40 shows an example in which the pilot separation of a preamble issupported based on maximum GI utilization mode of two types of SP mode.A pilot separation is automatically determined based on an FFT/GIcombination of a preamble with reference to maximum GI utilization modeof FIG. 45. The broadcast signal receiver may be aware of the pilotseparation of a preamble, that is, Dx, using information about theFFT/GI combination of the signaled preamble and information aboutmaximum GI utilization mode of FIG. 45. A broadcasting system maysupport all the combinations of the preamble structures shown in FIG. 40or subsets thereof.

FIG. 41 shows a preamble structure indicator according to anotherembodiment of the present invention.

In an embodiment, the preamble structure information may include a totalof 7 bits, and the first 3 bits of the 7 bits may indicate amodulation/coding scheme as in the embodiment of FIG. 38. Furthermore,the remaining 4 bits of the 7 bits may indicate an FFT size, GI samples,and a pilot separation as shown in FIG. 41. In this case, systemoverhead can be generally reduced.

FIG. 41 is an embodiment in which the pilot separation of a preamble issupported based on post-GI equalization mode of FIG. 46.

A pilot separation may be automatically determined based on an FFT/GIcombination of the preamble with reference to post-GI equalization modeof FIG. 46. The broadcast signal receiver may be aware of the pilotseparation with reference to information about the FFT/GI combination ofthe signaled preamble and information about post-GI equalization mode ofFIG. 46. In some embodiments, the broadcast signal receiver may use thesmallest value of the Dx values of an SP pattern, supported in acorresponding FFT/GI combination, as the pilot separation value of apreamble with reference to information about an FFT/GI combination ofthe signaled preamble and the SP pattern table of FIG. 47.

If the pilot separation of a preamble is supported as in FIG. 41 bytaking into consideration that data symbols having GI duration smallerthan GI duration of a preamble support both the two types of SP mode,there is an advantage in that the preamble can perfectly function as anedge symbol in all the cases. The broadcasting system may support allthe combinations of the preamble structures shown in FIG. 41 or subsetsthereof.

FIG. 42 shows a preamble structure indicator according to anotherembodiment of the present invention.

In an embodiment, the preamble structure information may include a totalof 7 bits, and the first 3 bits of the 7 bits may indicate amodulation/coding scheme as in the embodiment of FIG. 38. Furthermore,the remaining 4 bits of the 7 bits may indicate an FFT size, GI samples,and a pilot separation as in the embodiment of FIG. 41.

A pilot separation may be automatically determined based on an FFT/GIcombination of a preamble with reference to post-GI equalization mode ofFIG. 46. The broadcast signal receiver may be aware of the pilotseparation with reference to information about the FFT/GI combination ofthe signaled preamble and information about post-GI equalization mode ofFIG. 46. In some embodiments, the broadcast signal receiver may use thesmallest value of the Dx values of an SP pattern, supported in acorresponding FFT/GI combination, as the pilot separation value of thepreamble with reference to the information about the FFT/GI combinationof the signaled preamble and the SP pattern table of FIG. 47.

The embodiment of FIG. 42 also has an advantage in that a preamble canperfectly function as an edge symbol in all the cases because the pilotseparation of the preamble is supported.

However, in the embodiment of FIG. 42, Dx=3 is supported for acombination of 32K FFT and GI samples 3468. Post-GI equalization modehas been intended to have a dense SP pattern more than necessarycompared to GI duration, but is otherwise specially limited.Accordingly, post-GI equalization mode may have a different Dx valuedepending on a system. For example, in 32K FFT mode, if it is difficultto design a non-SP-bearing CP without using Dx=4, post-GI equalizationmode may be supported using Dx=3 instead of Dx=4 as in the embodiment ofFIG. 41. In this case, a broadcasting system may secure reserved bits byremoving a combination of 32K FFT and GI samples 3648 from a preamblestructure or may support post-GI equalization mode without a change asin FIG. 42 by taking into consideration a problem occurring due toexcessively great GI overhead.

A broadcasting system may support all the combinations of the preamblestructures of FIG. 42 or subsets thereof.

FIG. 43 shows a preamble structure indicator according to anotherembodiment of the present invention.

In an embodiment, the preamble structure information may include a totalof 7 bits, and the first 3 bits of the 7 bits may indicate amodulation/coding scheme as in the embodiment of FIG. 38. Furthermore,the remaining 4 bits of the 7 bits may indicate an FFT size, GI samples,and a pilot separation as in the embodiment of FIG. 41.

A pilot separation may be automatically determined based on an FFT/GIcombination of a preamble with reference to post-GI equalization mode ofFIG. 46. The broadcast signal receiver may be aware of the pilotseparation with reference to information about the FFT/GI combination ofthe signaled preamble and information about post-GI equalization mode ofFIG. 46. In some embodiments, the broadcast signal receiver may use thesmallest value of the Dx values of an SP pattern, supported in acorresponding FFT/GI combination, the pilot separation value of apreamble with reference to information about the FFT/GI combination ofthe signaled preamble and the SP pattern table of FIG. 47.

The embodiment of FIG. 43 also has an advantage in that a preamble canperfectly function as an edge symbol in all the cases because the pilotseparation of the preamble is supported.

Referring to the SP pattern table of FIG. 47, in 32K FFT, GI9_3072 andGI10_3648 support both Dx=8 and Dx=3. In this case, if only Dx=3 issupported in a preamble structure as in FIG. 42, the preamble is unableto function as an edge symbol in the case of Dx=8. Accordingly, in thecase of FIG. 43, such a disadvantage has been supplemented by addingmode for supporting Dx=8 to max GI mode.

A broadcasting system may support all the combinations of the preamblestructures shown in FIG. 43 or subsets thereof.

FIG. 44 shows a preamble structure indicator according to anotherembodiment of the present invention.

In an embodiment, the preamble structure information may include a totalof 7 bits, and the first 3 bits of the 7 bits may indicate amodulation/coding scheme as in the embodiment of FIG. 38. Furthermore,the remaining 4 bits of the 7 bits may indicate an FFT size, GI samples,and a pilot distance/separation as in the embodiment of FIG. 41.

In order to supplement the disadvantage of the embodiment of FIG. 42,instead of adding mode as in the embodiment of FIG. 43, Dx=8 may besupported in a GI10_3648 combination of 32K FFT as in the embodiment ofFIG. 44. If data SP Dx is 3, a preamble may select GI12_4864 of 32K FFTand support Dx=3. In the embodiment of FIG. 44, however, the number ofsignaling cases of a bootstrap is reduced, but overhead may be increasedif a data FFT size is 32K, GI mode is GI9_3072 or GI10_3648, and SP3_2is supported, for example.

FIG. 45 shows an SP-GI combination table of maximum GI utilization modein accordance with an embodiment of the present invention.

In FIG. 45, at least two pieces of GI/SP mode may be supported in apreamble with respect to each FFT size. In maximum GI mode of pieces ofGI modes in which a Dx basis=3, #7 (2048 samples) is for 8K FFT, #11(4096 samples) is for 16K FFT, and #12 (4864 samples) is for 32K FFT. Inmaximum GI mode of pieces of GI mode in which a Dx basis=4, #6 (1536samples) is for 8K FFT, #10 (3648 samples) is for 16K FFT, and #10 (3648samples) is for 32K FFT.

FIG. 46 shows an SP-GI combination table of post-GI equalization mode inaccordance with an embodiment of the present invention.

In FIG. 46, at least two pieces of GI/SP mode may be supported in apreamble with respect to each FFT size. In maximum GI mode of pieces ofGI modes in which a Dx basis=3, #7 (2048 samples) is for 8K FFT, #11(4096 samples) is for 16K FFT, and #12 (4864 samples) is for 32K FFT. Inmaximum GI mode of pieces of GI modes in which a Dx basis=4, #6 (1536samples) is for 8K FFT, #6 (1536 samples) is for 16K FFT, and #6 (1536samples) is for 32K FFT.

FIG. 47 shows an SP pattern table according to an embodiment of thepresent invention. FIG. 47 shows SP patterns supported by FFT and GImode.

FIG. 48 shows a modulation/coding mode table according to an embodimentof the present invention.

FIG. 48 shows ModCod combinations of L1 signaling Forward ErrorCorrection (FEC) used in a broadcast system according to an embodimentof the present invention. As may be seen from code rates andconstellations, mode numbers may be increased in order of an increasingtarget SNR.

As in the embodiment of FIG. 38, the 3 bits of the preamble structureinformation of the bootstrap may represent ModCod information ofL1-static information, included in the preamble, in seven types of mode.The code length, code rate, and QAM modulation method of each of theseven types of mode of the L1-static information are shown in FIG. 48.

In an embodiment, the number of bits of the preamble structureinformation of a bootstrap may be changed. The NoC of a preamble maybecome a minimum NoC. In the case of LDM, a preamble may be transmittedthrough a single layer. Furthermore, a preamble may be formed of SISOand transmitted. In the case of MISO, if the broadcast signal receiveris capable of receiving and decoding a preamble without additionalinformation, the preamble may be transmitted through an MISO method. Thenumber of preamble symbols may be signaled through L1-staticinformation. In another embodiment, the number of preamble symbols maybe calculated from the length of L1-dynamic information. In anembodiment, a preamble may have at least one symbol in the case of 8KFFT mode and may have at least two symbols in the case of 16K FFT mode.

FIG. 49 shows a preamble cell mapping method according to an embodimentof the present invention.

In an embodiment of FIG. 49, L1 signaling cells may be mapped to thefirst 2 8K FFT preamble symbols in zigzags. Furthermore, L1 signalingcells may be linearly mapped to preambles subsequent to the thirdpreamble. The linearly mapped L1 signaling cells may be more vulnerableto a burst error. However, L1-static information mapped to the first 2symbols can be rapidly obtained and decoded.

FIG. 50 shows a preamble cell mapping method according to anotherembodiment of the present invention.

In the embodiment of FIG. 50, L1 signaling cells may be mapped to all 8Kpreamble symbols in zigzags. That is, L1 signaling cells may be mappedto preamble symbols subsequent to the third preamble symbol, compared tothe embodiment of FIG. 49. L1 signaling cells may be robust against aburst error and may have a better time diversity gain with respect toall preamble symbols. However, latency in decoding L1 signalinginformation may be increased.

FIG. 51 shows preamble parameters according to another embodiment of thepresent invention.

The table of FIG. 51 shows parameters defining a preamble structure usedby a broadcasting system. The table of FIG. 51 shows an embodiment inwhich all the cases in which data symbols are supported for an FFT size,GI duration, and SP mode are also supported for a preamble. FEC mode ofL1 signaling corresponds to cases where the seven ModCod combinations ofFIG. 48 are used. LDM mode may be supported up to four layers. If allthe combinations of FIG. 51 are supported, 15 bits are required. In anembodiment of the present invention, however, a preamble structure isrestricted and a method of signaling a preamble structure using 7 bitsin a bootstrap by taking into consideration the limited number of bitsof a bootstrap is proposed in FIGS. 41 to 44.

In an embodiment, FEC of L1 signaling may be flexibly support. Apreamble FFT size may be supported in 8K/16K/32K mode, and the number ofpieces of FEC mode of L1 signaling may be restricted to 3 for eachpieces of FEC mode. The restricted L1 signaling FEC mode may bedetermined by taking into consideration the representative usage case ofeach FFT size and a target SNR of L1 signaling FEC.

In an embodiment, mode which uses a larger FFT size and has a highertarget SNR may be selected by taking into consideration that 8K FFT ischiefly used for mobile and 32K FFT is chiefly used for fixed reception.For example, L1 signaling FEC mode 1, 2, and 3 may be used for 8K FFT,L1 signaling FEC mode 1, 4, and 6 may be used for 16K FFT, and FEC mode1, 5, and 7 may be used for 32K FFT. The NoC of a preamble may be fixedto a minimum NoC by taking into consideration the capacity of abootstrap, and the NoC, SP pattern, FFT/GI, LDM setting, and SISO/MIMOof data symbols may be signaled in a preamble.

In another embodiment, FEC ModCod of L1 signaling information may beflexibly supported instead of fixing the FFT size of a preamble to 8KFFT.

FIG. 52 shows the structure of a signal frame according to an embodimentof the present invention.

In FIG. 52, the first symbol after a bootstrap and last symbol of aframe may become edge symbols (P/E & D/E). The edge symbol may have adenser SP pattern than data symbols. Accordingly, the edge symbol canimprove channel estimation performance near a frame boundary.

The SP pattern of the edge symbol may use Dy=1 in Dx*Dy and may bedetermined to be only by Dx. Accordingly, the edge symbol has higherpilot density than data symbols using a pilot pattern of Dx*Dy. Forexample, if Dx=3 and Dy=2, a pilot separation in the frequency directionwithin a single symbol is 6. However, if D=3 and Dy=1, a pilotseparation in the frequency direction within a single symbol may be 3.In this specification, the structure of the preamble pilot correspondsto the structure of such an edge symbol.

A preamble can be rapidly obtained because the first symbol of thepreamble has such an edge symbol. Only frequency interpolation may benecessary for channel estimation. In an embodiment, a CP may be used inan edge symbol.

FIG. 53 shows the structure of a signal frame according to anotherembodiment of the present invention.

If the FFT sizes of a preamble and a data part within a signal frame aredifferent as in FIG. 53, the first symbol of the data part may become anedge symbol (D/E). In this case, the preamble may have the pilotstructure of the aforementioned Dx separation so that the preamble israpidly obtained. That is, all the preamble symbols may have thestructures of edge symbols. Accordingly, time interpolation for channelestimation may become unnecessary.

FIG. 54 shows the structure of a signal frame according to anotherembodiment of the present invention.

In FIG. 54, an edge symbol (D/E) may be configured for each subframe.That is, the first or last symbol of each subframe may become an edgesymbol with respect to at least one subframe included in the signalframe. A data multiplexing (TDM/LDM/LTDM) method may be independentlyapplied to each subframe. Payload mapping of a data part may also beindependently applied to each subframe.

In the embodiment of FIG. 54, all the preambles have the pilotstructures of edge symbols. Furthermore, the last symbol of a firstsubframe having a first FFT size (FFT size #1) and the first and lastsymbols of a second subframe having a second FFT size (FFT size #2)correspond to an edge symbol (D/E).

If the structure of an edge symbol is used in each subframe as in theembodiment of FIG. 54, the edge symbol may also be called a subframeboundary symbol.

FIG. 55 shows the structure and signaling of a signal frame according toan embodiment of the present invention.

A bootstrap may signal a major/minor version and may signal a BStermination by a phase inversion.

As described above, a bootstrap may signal preamble structureinformation. The preamble structure information indicates ModCodinformation and FFT/GI information for the preamble.

The preamble signals the structure of data symbols. In the structure ofdata symbols, a preamble may signal at least one of an FFT size, FI, anSP pattern, and the NoC. Furthermore, the first preamble symbol maysignal the structure of subsequent preamble symbols. In an embodiment,the first preamble symbol may signal the number of additional preamblesymbols and the structure of additional symbols. The first preamble maysignal at least one of an FFT size, a GI, an SP pattern, and NoCinformation for the additional preamble symbols.

FIG. 56 shows a method of transmitting a broadcast signal according toan embodiment of the present invention.

As described above in relation to the broadcast signal transmitter andthe operation thereof, the broadcast signal transmitter mayinput-process the input data using the input formatting module andoutput the data of at least one Data Pipe (DP), that is, the data of atleast one Physical Layer Pipe (PLP), (S56010). Furthermore, thebroadcast signal transmitter may perform error-correction processing orFEC-encoding on data included in at least one PLP using the BICM module(S56020). The broadcast signal transmitter may generate a signal frame,including the data of the at least one PLP, using the framing module(S56030). The broadcast signal transmitter may insert pilots into thesignal frame using the pilot insertion module (S56040) and OFDM-modulatethe signal frame using the IFFT module (S56050).

The signal frame includes a bootstrap, a preamble, and a data part. Thedata part may include at least one subframe. Furthermore, the insertedpilots include Continual Pilots (CPs) and Scattered Pilots (SPs). In anembodiment, preamble pilots may be inserted into the preamble, and asubframe boundary preamble may also be inserted into a subframe boundarysymbol.

The bootstrap is placed at the start portion of a broadcast signal frameand has a fixed signal configuration (e.g., a sampling rate, a signalbandwidth, subcarrier spacing, and a time domain structure). Thebootstrap signal includes preamble structure information about thepreamble. The preamble structure information may indicatemodulation/coding mode of the preamble, an FFT size, a GI length, and apilot pattern as described above in relation to FIGS. 38 to 48.

The preamble includes at least one preamble symbol. The at least onepreamble symbol carries Layer 1 (L1) signaling data for the signalframe. The L1 signaling data provides essential information formingphysical layer parameters. The L1 signaling data may include L1-basicdata (L1-static data) and L1 detail data (L1-dynamic data). The L1-basicdata includes static information about the signal frame and maydefine/include parameters for decoding the L1 detail data. The L1 detaildata may include information for decoding the data part.Modulation/coding mode included in the preamble structure informationmay indicate modulation/coding mode of the L1-basic data.

The first preamble symbol of the preamble may includepreamble_symbol_number information indicating the number of preamblesymbols. In this case, the preamble_symbol_number information mayrepresent the number of additional preamble symbols other than the firstpreamble symbol. In an embodiment, the preamble_symbol_numberinformation may be included in the L1-basic data.

The first preamble symbol of the preamble may have a minimum NoC. Theminimum NoC may correspond to a case where an NoC reduction coefficientis 4 (i.e., C_red_coeff=4) in Table 34. Furthermore, the first preamblesymbol may include information related to the number of carriersindicating the number of carriers of the remaining preamble symbols. Asdescribed above, the information related to the number of carriers (NoCrelated information) may be signaled as an NoC reduction coefficient.

The preamble symbol includes preamble pilots. In the case of preamblepilots, as described above, Dy=1, and Dx may be indicated by a pilotpattern of preamble structure information.

FIG. 57 shows the synchronization and demodulation module of thebroadcast signal receiver in accordance with an embodiment of thepresent invention.

FIG. 57 shows the submodules of the synchronization and demodulationmodule 9000 shown in FIG. 9.

The synchronization and demodulation module includes a tuner 57010 fortuning a broadcast signal, an ADC module 57020 for converting an analogsignal into a digital signal, a preamble detector 57030 for detecting apreamble included in a received signal, a guard sequence detector 57040for detecting a guard sequence included in the received signal, awaveform transform module 57050 for performing OFDM demodulation, thatis, FFT, on the received signal, a reference signal detector 57060 fordetecting a pilot signal included in the received signal, a channelequalizer 57070 for performing channel equalization using the extractedguard sequence, an inverse waveform transform module 57080, a timedomain reference signal detector 57090 for detecting the pilot signal ina time domain, and a time/frequency sync module 57100 for performingtime/frequency synchronization on the received signal using the preambleand the pilot signal.

The waveform transform module 57050 may also be designated as an FFTmodule for performing OFDM demodulation. The inverse waveform transformmodule 57080 is a module for performing transform opposite FFT and maybe omitted according to embodiments or may be replaced with anothermodule for performing the same or similar function.

FIG. 57 corresponds to a case where the broadcast signal receiverprocesses a signal, received by a plurality of antennas, through aplurality of paths. In FIG. 57, the same modules are illustrated inparallel, and a redundant description of the same module is omitted.

In an embodiment of the present invention, the broadcast signal receivermay detect and use a pilot signal using the reference signal detector57060 and the time domain reference signal detector 57090. The referencesignal detector 57060 may detect the pilot signal in a frequency domain.The broadcast signal receiver may perform synchronization and channelestimation using the characteristics of the detected pilot signal. Thetime domain reference signal detector 57090 may detect the pilot signalin the time domain of a received signal. The broadcast signal receivermay perform synchronization and channel estimation the characteristicsof the detected pilot signal. In this specification, at least one of thereference signal detector 57060 for detecting the pilot signal in thefrequency domain and the time domain reference signal detector 57090 fordetecting the pilot signal in the time domain may be called a pilotsignal detector or a pilot detector. Furthermore, in this specification,a reference signal means a pilot signal.

FIG. 58 shows a method of receiving a broadcast signal according to anembodiment of the present invention.

As described above in relation to the broadcast signal receiver and theoperation thereof, the broadcast signal receiver may OFDM-demodulate areceived broadcast signal using the Fast Fourier Transform (FFT) module(S58010). The broadcast signal receiver may detect pilots, included inthe broadcast signal, using the pilot detector (S58020). The broadcastsignal receiver may perform synchronization, channel estimation, andcompensation on the broadcast signal using the detected pilots. Thebroadcast signal receiver may parse the signal frame of the broadcastsignal using the frame parsing module (S58030). The broadcast signalreceiver may extract and decode preamble data included in the signalframe and may extract a required subframe or PLP data using L1 signalinginformation obtained from the preamble data. The broadcast signalreceiver may convert the PLP data extracted from the broadcast signalinto a bit domain using the demapping and decoding module and mayFEC-decode the PLP data (S58040). Furthermore, the broadcast signalreceiver may output the PLP data in the form of a data stream using theoutput processing module (S58050).

The signal frame includes a bootstrap, a preamble, and a data part. Thedata part may include at least one subframe. Furthermore, the insertedpilots include Continual Pilots (CPs) and Scattered Pilots (SPs). In anembodiment, preamble pilots may be inserted into the preamble, and asubframe boundary preamble may also be inserted into a subframe boundarysymbol.

The bootstrap is placed at the start portion of a broadcast signal frameand has a fixed signal configuration (e.g., a sampling rate, a signalbandwidth, subcarrier spacing, and a time domain structure). Thebootstrap signal includes preamble structure information about thepreamble. The preamble structure information may indicatemodulation/coding mode of the preamble, an FFT size, a GI length, and apilot pattern as described above in relation to FIGS. 38 to 48.

The preamble includes at least one preamble symbol. The at least onepreamble symbol carries Layer 1 (L1) signaling data for the signalframe. The L1 signaling data provides essential information formingphysical layer parameters. The L1 signaling data may include L1-basicdata (L1-static data) and L1 detail data (L1-dynamic data). The L1-basicdata includes static information about the signal frame and maydefine/include parameters for decoding the L1 detail data. The L1 detaildata may include information for decoding the data part.Modulation/coding mode included in the preamble structure informationmay indicate modulation/coding mode of the L1-basic data.

The first preamble symbol of the preamble may includepreamble_symbol_number information indicating the number of preamblesymbols. In this case, the preamble_symbol_number information mayrepresent the number of additional preamble symbols other than the firstpreamble symbol. In an embodiment, the preamble_symbol_numberinformation may be included in the L1-basic data.

The first preamble symbol of the preamble may have a minimum NoC. Theminimum NoC may correspond to a case where an NoC reduction coefficientis 4 (i.e., C_red_coeff=4) in Table 34. Furthermore, the first preamblesymbol may include information related to the number of carriersindicating the number of carriers of the remaining preamble symbols. Asdescribed above, the information related to the number of carriers (NoCrelated information) may be signaled as an NoC reduction coefficient.

The preamble symbol includes preamble pilots. In the case of preamblepilots, as described above, Dy=1, and Dx may be indicated by a pilotpattern of preamble structure information.

The broadcast signal receiver may perform signal discovery, coarsesynchronization, frequency offset estimation, and initial channelestimation using a bootstrap. Furthermore, the broadcast signal receivermay process the service data or PLP data of a data part by sequentiallydecoding a preamble, L1-basic data, and L1 detail data.

The broadcast signal receiver may be aware of the structure of apreamble through a bootstrap. However, in the case of the NoC, thebroadcast signal receiver may process the first preamble symbol based ona predetermined minimum NoC, and the NoC of subsequent preamble symbolsmay be obtained through NoC-related information about the decoded firstpreamble symbol. Accordingly, the broadcast signal receiver may processthe subsequent preamble symbols based on a corresponding NoC based onthe result of the decoding of the first preamble symbol.

In accordance with an embodiment of the present invention, a signaloverhead reduction and signaling flexibility can be achieved by definingpreamble structure information transmitted in a bootstrap. Furthermore,signaling overhead can be reduced by fixing an FFT size, a GI, and apilot pattern signaled in preamble structure information with respect toall signaled preambles, and preamble processing speed of the broadcastsignal receiver can be improved by simplifying a signal configuration.In this case, the throughput of a broadcasting system can be flexiblycontrolled depending on a channel situation and the amount oftransmitted data can be increased by fixing the NoC of only the firstpreamble symbol to a minimum and signaling the NoC of subsequentpreamble symbols.

Pilot density can be increased by configuring preamble symbols using apreamble pilot of Dy=1. Accordingly, preamble symbols can be rapidlyobtained, and channel estimation and synchronization trackingperformance can be improved. A preamble pilot may be used to decode adata part using one of Dxs defined in the data part. In particular, sucha configuration can improve data processing speed of the broadcastsignal receiver because processing latency of a data part can be reducedonly when a preamble is rapidly processed.

The amount of L1 detail data may be changed depending on a service andthe configuration of PLP data included in a broadcast signal.Accordingly, the number of preamble symbols for carrying L1 signalingdata may also be changed. However, a bootstrap needs to be restricted tothe very limited amount of data. The reason for this is that thebootstrap has a system identification function, that is, a fixedconstruction known to all the broadcast signal receivers. Accordingly,in an embodiment of the present invention, the number of preamblesymbols is transmitted using the first preamble. In particular, symbolnumbers are carried as the number of the remaining preambles other thanthe first preamble. Accordingly, the broadcast signal receiver can checkthe number of subsequent preambles by decoding information about thefirst preamble and process a signal frame based on the number ofsubsequent preambles.

L1 detail data can separately configure an ModCod configuration becauseModCod information of a bootstrap is signaled with respect to onlyL1-basic data. Accordingly, system operation flexibility can beimproved. ModCoD information about L1 detail data may be included inL1-basic data and signaled.

Those skilled in the art will understand that the present invention maybe changed and modified in various ways without departing from thespirit or range of the present invention. Accordingly, the presentinvention is intended to include all the changes and modificationsprovided by the appended claims and equivalents thereof.

In this specification, both the apparatus and the method have beendescribed, and the descriptions of both the apparatus and method may bemutually supplemented and applied.

Various embodiments have been described in the best form forimplementing the present invention.

The present invention is used in a series of broadcast signal providingfields.

It is evident to those skilled in the art will understand that thepresent invention may be changed and modified in various ways withoutdeparting from the spirit or range of the present invention.Accordingly, the present invention is intended to include all thechanges and modifications provided by the appended claims andequivalents thereof.

What is claimed is:
 1. A broadcast signal transmitter, comprising: aninput formatting module configured to input process input data and tooutput at least one Physical Layer Pipe (PLP) data; a Bit Interleavedand Coded Modulation (BICM) module configured to perform errorcorrection processing on the PLP data; a framing module configured togenerate a signal frame comprising the PLP data, the signal framecomprising a bootstrap, a preamble, and a data part; a pilot insertionmodule configured to insert pilots into the signal frame; and an InverseFast Fourier Transform (IFFT) module configured to Orthogonal FrequencyDivision Multiplexing (OFDM)-modulate the signal frame, wherein thebootstrap comprises preamble structure information about the preamble,the preamble comprises at least one preamble symbol, and the at leastone preamble symbol carries L1 signaling data for the signal frame. 2.The broadcast signal transmitter of claim 1, wherein the preamblestructure information indicates modulation/coding mode, an FFT size, aGuard Interval (GI) length, and a pilot pattern of the preamble.
 3. Thebroadcast signal transmitter of claim 1, wherein: a first preamblesymbol of the preamble comprises preamble_symbol_number informationindicating a number of the preamble symbols, and thepreamble_symbol_number information indicates a number of additionalpreamble symbols other than the first preamble symbol.
 4. The broadcastsignal transmitter of claim 1, wherein: a first preamble symbol of thepreamble has a minimum number of carriers (NoC), and the first preamblesymbol comprises NoC-related information indicating an NoC for remainingpreamble symbols.
 5. The broadcast signal transmitter of claim 1,wherein: the preamble symbol comprises preamble pilots, and for thepreamble pilots, a number of symbols forming one pilot sequence in atime direction Dy is 1, and a separation of pilots in a frequencydirection Dx is indicated by the pilot pattern of the preamble structureinformation.
 6. The broadcast signal transmitter of claim 2, wherein:the L1 signaling data comprises L1-basic data and L1 detail data, theL1-basic data comprises static signaling information about the signalframe and defines parameters for decoding the L1 detail data, the L1detail data comprises information for decoding the data part, and themodulation/coding mode indicates modulation/coding mode of the L1-basicdata.
 7. A method of transmitting a broadcast signal, comprising: inputprocessing input data and outputting at least one Physical Layer Pipe(PLP) data; performing error correction processing on the PLP data;generating a signal frame comprising the PLP data, the signal framecomprising a bootstrap, a preamble, and a data part; inserting pilotsinto the signal frame; and Orthogonal Frequency Division Multiplexing(OFDM)-modulating the signal frame, wherein the bootstrap comprisespreamble structure information about the preamble, the preamblecomprises at least one preamble symbol, and the at least one preamblesymbol carries L1 signaling data for the signal frame.
 8. The method ofclaim 7, wherein the preamble structure information indicatesmodulation/coding mode, an FFT size, a Guard Interval (GI) length, and apilot pattern of the preamble.
 9. The method of claim 7, wherein: afirst preamble symbol of the preamble comprises preamble_symbol_numberinformation indicating a number of the preamble symbols, and thepreamble_symbol_number information indicates a number of additionalpreamble symbols other than the first preamble symbol.
 10. The method ofclaim 7, wherein: a first preamble symbol of the preamble has a minimumnumber of carriers (NoC), and the first preamble symbol comprisesNoC-related information indicating an NoC for remaining preamble symbolsother than the first preamble symbol.
 11. The method of claim 7,wherein: the preamble symbol comprises preamble pilots, and for thepreamble pilots, a number of symbols forming one pilot sequence in atime direction Dy is 1, and a separation of pilots in a frequencydirection Dx is indicated by the pilot pattern of the preamble structureinformation.
 12. The method of claim 8, wherein: the L1 signaling datacomprises L1-basic data and L1 detail data, the L1-basic data comprisesstatic signaling information about the signal frame and definesparameters for decoding the L1 detail data, the L1 detail data comprisesinformation for decoding the data part, and the modulation/coding modeindicates modulation/coding mode of the L1-basic data.